They aren't worried about robots, they're worried about spam. The "we don't think you're human" error message was just to sound cute. Automation is fine; it's likely the poster pushed a spammy link or something that set off their filters.
Re:GitHub Thinks I'm a Robot
by sillysaurus3 on Saturday June 04, 2016 @03:03PM
(#11837516)
No worries. This is triggered by heuristics that make it look like an account is compromised, like creating spam gists. Normal use cases won't trigger it, and if it does, support takes care of you within 15 minutes. That was my experience, at least.
There are robots everywhere: for example, the Rust's github repos won't work the same without bors or highfive.
If I remember correctly, the github itself definitely used to allow robots for such use cases.