Are you saying you prefer to deny others the ability to directly interact with the same git structure you have in their git tools (by simply fetching from a remote), instead forcing them to apply a patch from an email and hope everything goes right? If so, why would you do that? This seems like it's a little idiosyncrasy you have that has little to do with the actual topic at hand.
Sounds like your problem isn't with pull requests, but with neophytes you have experienced in github projects you looked at, who do not rebase and force push.
In the majority of projects (excepting those run by neophytes) i participate in, whether on github or off, there has always been a clear line of pull requests required to be clean, meaning not only should the commits not contain cruft-cleanup, they also have to be on HEAD, contain Changes-file adjustments, contain tests, etc. When patch makers get these instructions and force-push that kind of thing, it's a breeze for maintainers to do a fetch, then compare their local marker on the requesters branch with the new state of the remote branch.
Having a requester go "no, i only send emails" in that situation would not be constructive.
