I feel @Rockslayer isn’t a union organiser. Or if they are, they’re a very poor one with that attitude/mindset.

Or maybe they know how to pick their battles? Yeah Discord isn't ideal, but is it really so bad that it's worth the significant effort it would take to try and get people to switch, compared to all the other things they could be spending their effort on?

That's a decision only they can make for themselves. And your condescending attitude does nothing but reflect poorly on you.