I don't think we have to worry about software patents as half of them are so retarded they won't hold up in a court of lay anyway.
The problem is that the US Patent Office has gone completely nutz. They grant patents for some of the damnedest things these days, that Microsoft really doesn't have much choice other than to file these things. They have the deepest pockets around, and that's a ripe target for someone else to come along and beat them to a "patent", that could have them in a position to basically settle out of court, as fighting the suit would be more expensive.
That, in turn, could lead to an "open season" on bleeding them with these frivolous patents. To prevent that, they aggressively file first, regardless of the merits of the patent. Lawyers run amok is what's causing this.
