I support the sentiment, but the actual issue here that nobody ever brings up is that the FOSS solutions for chat all suck. It's not just network effect. IRC is

I support the sentiment, but the actual issue here that nobody ever brings up is that the FOSS solutions for chat all suck. It's not just network effect. IRC is not friendly to set up for people who are not tech-savvy, and it sorely lacks a lot of features that people use Discord for. Matrix isn't much better, since the only user-friendly Matrix client is just trying to copy Discord, and in doing so ends up looking and feeling like a cheap knockoff. If you want to shame people for using the most effective chat application, provide an alternative that's actually good (and Discord is not a high bar to beat; it actually sucks too, there's just nothing better).