Trolls likely have access to phone number farms though. And in some parts of the world it's extra cheap to mass-register phone numbers. Trolls wouldn't be harmed in a data leak, only normal users get hurt.

Most trolls aren't the kind of trolls that run large scale networks, they're the 12 year olds you triggered by saying BLM

Once a phone is banned though, it's unusable again at least in a given server. Discord will treat it like an IP ban (which they also do).

Phone numbers may be required to bring order to a vast international user base, but a few dozen devs and a small user community can function without invasive moderation tactics.

The communities I'm in don't require a phone number and very rarely gets trolls. Proper moderation is the most important part. Occasionally there's a spambot, but they're just hacked accounts from pre-existing real users, and as someone that uses a VPN with Discord, I'd prefer to not be treated as an evil-doer please.

Sure, are the communities you're in tens of thousands of users or more? Because things change really quickly depending on how many users are active, if it's a community server, and the subject matter. Even a programming Discord is a hell hole. You cannot have enough mods ever. Things fall through the cracks and people get hurt. You can't moderate DMs or know the wellbeing of tens of thousands of your users who are being harassed in DMs and have no idea how to get help. Discords full of a lot of youth.

Theres users who rotate community servers on a VPN / new spun up alts. They are relentless. I noticed the communities that are massive and do not have this problem to this extend all require phone number.