I'm sorry to see that you've felt spurned by STEM. Having been around it in several fields I've not seen this circl jerk in real life, but from what I've read it must be happening somewhere. That said, even if it was all present, it's not why scientists aren't more vocal and preemptive. There's three main reasons why they aren't: 1) A lot of scientists don't feel it is their place. They're trained in research, not public policy, and therefore should stick to what they know. 2) It's not easy to break down scientific findings in a way that is meaningful and interesting to the public/legislatures.
Additionally science seems to have an uphill battle, as so many people seem to take delight in how little science they're familiar with and just simply refuse to learn anything that doesn't fit inside their preestablished world views. 3) It's impossible to predict what arguments will be used by antiabortion lobbyists before they actually start pitching it.