[rsync]

"Pushing their problems down to the user in this way feels shitty, at best ..."

You've identified exactly what is going on.

Platforms such as this are facing a brutal, relentless scam/spam onslaught and I think we can conclude that no, in fact, they do not have an elegant solution to it.

The closest things I have seen to real, elegant solutions to this problem are:

1) metafilter charging $5 per new registration - I think you can send them a five dollar bill

2) lobste.rs with their chained/linked account referral which puts the cost on the referrer and introduces some personal responsibility for new signups, etc.

The common solution is to demand a SIM identity - any SIM identity - "for your protection". That's the best solution they have come up with - any functioning truly mobile number (backed by a SIM card, not VOIP) is enough sand in the gears to slow down the onslaught ...