The Houston case was just an intentional shot across the bow by the attorney for the City, which I think the Mayor or other City officials have acknowledged may have gone to far.
You have a bunch of people trying to change or affect what the City was doing so the City attorney, knowing full well the effect of demanding copies of all sermons, came out throwing grenades.
It's a legitimate litigation tactic, but it backfired somewhat. The other side, including the pastors, had a right to make a big political deal of it, which they did.
The idea that religious or free speech rights are being trampled, though, I don't buy.