Yeah indeed. I have written but not submitted patches to a project (OpenSBI) because it made the submission process super complicated, requiring signing up to a mailing list, learning how to set up git send-email.
I don't see how he can think creating a GitHub account (which almost everyone already has) is a big barrier when he freely admits his process is incomprehensible.
I don't buy the GitHub locks you in either. It's pretty easy to copy issues and releases elsewhere if it really comes to it. Or use Gitlab or Codeberg if you must.
https://docs.codeberg.org/advanced/migrating-repos/
Any of those are far better than random mailing lists, bugzilla, and emailed patch files.
Putty is great but please don't listen to this.