It's better than wasting peoples' time, but it's still a really shit workaround.
The PR can be pulled from any git client and could easily be imported into their preferred repo. This could be automated.
If they've already got a bot that automatically comments and closes PRs, they've already done the hard parts, but they chose to be hostile and unhelpful instead of doing it properly.
(Or, nobody thought of doing what I just suggested.)
The social network of the future: No ads, no corporate surveillance, ethical design, and decentralization! Own your data with Mastodon!