GitHub offers the service for free and doesn't publish or enforce any specific limit on number of commits. I see nothing wrong with a user pushing as many commits to it as possible. It's not his problem when to stop it.
This is also how I feel about the Tor project getting their knickers twisted over people who do research on the live network. If the network can't handle it, then it's not resilient to attack. Asking people nicely not to do stuff that degrades your product will not make the product suddenly anti-fragile.
Well, in the case of the Tor network its whole premise is that it's resilient to attack. So either it is or it isn't. If it's resilient but only as long as people treat it nicely, then it's not actually resilient. And anyone who can demonstrate that is doing a public service. It would be irresponsible to discover a flaw and not disclose it, or to continuously exploit it. But it's not irresponsible to look for the flaw in the first place.
In the case of GitHub, it's owned by a nearly trillion dollar corporation. Nobody is hurting some mom and pop business here.
This is also how I feel about the Tor project getting their knickers twisted over people who do research on the live network. If the network can't handle it, then it's not resilient to attack. Asking people nicely not to do stuff that degrades your product will not make the product suddenly anti-fragile.