I always think back to that "if you don't talk to them, someone else will" image that used to circulate. Reactionary ideas should definitely be called out and deried, but putting in the time and effort to reach out to people who are at least possibly sympathetic to your views is one of the small (but important) things any leftist can do.
I'll never forget in one of my classes way back when we were given example cases and had to choose the "ethical" response. Needless to say, the only ethical actions were ones that benefited the company directly.
My favorite was a hypothetical about finding out your coworker was about to be fired and basically have his life destroyed, and the "correct" action was to not tell him because, hey - what if he did something to hurt the company before he was unceremoniously booted out :shrug-outta-hecks: