Many of the behaviors you’re concerned with are, I think, a consequence of the increasingly hostile perception of centrists. It used to be that folks like us were to be courted for our support and our votes. Now the conventional wisdom is that we’re to blame for all of society’s ills because we inadvertently sabotaged Hillary Clinton’s bid for the presidency. I think the tribal behaviors you’re witnessing among some centrists, and the IDW in particular, are mostly instinctive fight-or-flight responses to that situation. I also think it’s why those tribal behaviors have a noticeably conservative flavor to them; conservatives just haven’t been as hostile towards centrists as progressives have, though I suspect that wouldn’t be the case if Republicans had lost the 2000 and 2016 elections despite winning the popular votes in both.
In any case, my hope is that this all just a phase that will pass with time, most likely after President Trump has left office and progressives feel like the existential threat they believe he represents has at least been temporarily neutralized. Once that happens, the hostility directed at centrists should start to subside, which in turn should, I hope, encourage centrists to get back to the business of putting truth before tribalism.