this isn't out of context. the bible does indeed condone selling your daughters into slavery as well as a ton of other things that are clearly morally wrong.
the ones you've mentioned are all from the Tanakh though, you realise. christians would just distance themselves from these comments by claiming that these things have all been superceded. The New Testament is their true inspired word of God, and if they can claim that the NT overrules anything in what they call the Old Testament (a slightly re-edited version of the Jewish Tanakh) then you'll get nowhere.
It's those Matthew, Titus, Timothy, Corinthians passages you want to use, because they can't really distance themselves from those. Having said that though, i just checked out the two Matthews and the 1st Timothy quote you linked to and none of them are out of context. The Matthews are not hard for a christian to refute since they are so obviously allegorical. the 1 Timothy one is indeed controversial, but it isn't out of context. The author of this letter is actually advocating that slaves have respect for their masters, in order to glorify their God. This is the christian principle of living by example. why make trouble in this world when you've got heaven waiting for you in the next? That's what the writer of 1 Timothy is trying to say, because remember, at this point, i don't think they actually had a clear sense within christianity of the afterlife. in my opinion, the author is trying to inject the afterlife into christianity. He is saying "behave this way, why? because if you do, you get this excellent afterlife!".
Contrary to what christians will tell you, i don't think the references to the "kingdom of Heaven" in the gospel of Luke refer to an afterlife, and i am not convinced that all the references to eternal life in the gospel of John are about an afterlife either. In my opinion, the heavenly afterlife was added at some point in the writing of the early christian books, by people like the author of 1 Timothy, and was probably co-opted from other religions. In my opinion there's little or no evidence that Jesus himself actually described the afterlife as christians now understand it.
Anyway, basically i think it's much better to take bible passages in context, because you'll get a much better argument out of it.
by the way, i don't agree that the bible was designed that way for a reason. what happenned with the Tanakh is that the Jewish people honed their wisdom and law into some books, and then carried them around wherever they went (The Torah). Prophets would add their own books (The Nevi'im) and there are some other writings also(The Kethuvim), like the psalms, Song of Songs and the book of Job. These writings, collectively known as the Tanakh (it's an acronym, for Torah, Nevi'im, Kethuvim) were subtlely but significantly reordered by the christians and retranslated by them too, to generate the backstory for their religion. Remember that the Tanakh took at least a couple of millenia to reach its current form (very much the same form it was in at the time christianity started to pop up).
The christian scriptures are a totally different matter. These writings come from a sociopolitical melting pot. The middle east was in a huge time of turmoil at the time due to the Roman empire and so on. The christian writings were all written *after* the sack of Jerusalem and the burning of the Temple. Jesus' life supposedly happened a few decades *before* this. In the first century Jerusalem had been wiped out, the Jewish faith was fragmented and no longer centralised and many messianic cults were springing up (as they had been for a century or two, but with the aftermath of war, these took on a greater significance, i imagine).
So everybody was writing different things. Some of these writings were not "christian" by today's standards, and some were. Many were reinterpretations of older philosophies, often Greek or other pagan cultures. From the first to fourth centuries, various people took it upon themselves to identify which of these writings were divinely inspired and which were the work of the devil. Eventually the emperor Constantine
sat down with a bunch of Bishops at Nicea to decide once and for all (this is immediately after this pious church father had "united" the Roman empire and "ended anti-christian persecution" by waging war for 22 continuous years on all its colonies). They came up with the 22 documents that are in the "New Testament". These documents are all of unknown authorship, except three letters of St Paul (who never met Jesus). Then once they'd decided on the Holy books they wanted to keep, they declared all other religious writings to be heresy and set about destroying every copy. Several dozen of these survive today only by total chance, and often there is only one copy of books such as the gospel of Judas the twin and the Secret book of John. The gospel of Thomas is one of the most controversial, because it may be earlier than other christian writings, but i won't go into that here. One other interesting thing, any Bishops who didn't agree at Nicea with Constantine's selection of Holy books was then excommunicated from the Roman Catholic church after the meeting was finished!
The point is, the Tanakh (which is the part of the bible that critics generally take pot shots at) is not meant for christians, they just co-opted it for their own ends. The Jews have more than one very robust framework for exploring the Tanakh, compared with that the christian effort at understanding it is nothing but a joke.
The New Testament however, for all their planning at Nicea, and for all their efforts to destroy all heresies, the christians have ended up with documents that do not agree, and not only have different agendas, but actually have different worldviews. The gospels make a hell of a lot more sense if you put aside your preconceptions. For example, don't assume heaven or hell exists, don't assume that the gospels are all talking about the same kind of christianity as each other. Plenty of core christian beliefs have been added later, the idea of crucifixion as the route to salvation, this is not really stated in all the New Testament books. It's definitely possible to read some of the New Testament without reading anything to suggest that Jesus actually died to redeem our sins. This is all retroactive continuity, usually using bits of the gospel of John and sections of St Paul's letters (many of which were probably written by other people, St Paul's disciples?) to fill out ambigous parts elsewhere in the New Testament.
So basically i think the christians would have been a lot happier if their book wasn't so ambiguous, but history's not like that. The more i look at the development of the New Testament (with particular interest in the books which were left out), the more i realise that there is a good case to say that the New Testament was not divinely inspired at all, or it would not be so ambiguous and contrary.