I've unionized in real life and I've come to the conclusion that only two things can change a person's mind to adopt more leftist politics, at least in a group setting. (Individually people are all over the place and random stuff can happen in their lives)

The only two things I've been able to use are: offering them something or embarrassing them. You offer them a good union deal, or you have enough comrades together to shout down any dissenters. The internet probably doesn't work quite that way but who knows. We're not here to convince people of anything, we're here to relax or have a laugh.

You're probably right that more people here should try to answer good faith questions. But most of us are here in the first place out of frustration. We all feel alone and alienated in our daily lives, so it's nice to come around and chill with like-minded people. Our first instinct when we see someone dissenting is with the same frustration we typically feel. We're too stressed.