Replace "colleagues" with "siblings," and "toxicity" with "alcoholic parent." Maybe that will make it more clear. By "going along with" the situation, you are enabling it. Of course, it's complicated. Enabling a bad situation might provide cover for other people (as you suggested), but it also perpetuates the bad situation. My personal belief is that if I can get out without endangering myself or others, I should. My act will help empower others to make the same decision.

> How's "protecting your colleagues from a toxic space is a recipe for more toxicity"? And there should be no "trying" there. I fail to see a line that you drawn.

You almost certainly don't have the power to "protect your colleagues from a toxic workplace," especially by the mere act of not quitting. So all you can do is try and fail.

If you leave, you have a better chances of actually making things better for yourself, and that may cause the dominoes to fall and get others do the same.