the defense was practice squad and rookies. Tonight they had their core guys sans rapp, hill and hoecht. The defense can not be this bad missing three starters. It just can't.
They got stops later in the game in part because Houston was fine with punting on a few of those 4th and short to midrange because they knew there defense had the game under control. If Houston needed to they could have been more aggressive later in the game, there was no reason to do that however.