Right. Stick with the tried and true defenses like Arizona.
Defense is mostly a crapshoot. Not as much as kickers, but close. Whenever I'm debating on a streamer, I remind myself that I'll most likely get league-average points (in my case, ~7) from whichever D I pick. Yes, it's better to skew toward talent over match-up, but sometimes you're just going to get it wrong. Clearly my decision to start Miami over Philly didn't work out, but I think the thought process was solid.
Also, what is the alternative? Reach a few rounds early in the draft for an elite D? That doesn't have the best track record either. Also, streaming is always going to be a fallback strategy. If you luck into an elite D, sure, stick with them. But once you're in-season, there's not much you can really do.