[koenigdavidmj]

Is there any incentive or law that causes Github to have a DMCA web form?

If it's possible, then it would be a good act of protest to require individually signed (by an actual person with a pen, not a picture of a signature), individually snail-mailed requests. This would at least make the process take O(n) time and O(n) money, making it a bit harder to abuse.

[notyourday]

Yes, by following DMCA procedures Github stops being liable for its users copyright infringement actions (safe harbor). Should Github not follow procedures defined in DMCA, Github would be on a hook.

[koenigdavidmj]

I'm describing a form of malicious compliance. Is there a legal requirement that the request be a web form? Or is it allowed to provide only a mailing address?

[notyourday]

It can be anything that provides a commercially reasonable way to contact the entity. So fax/p.o. box/email/web form etc all work.