That's the way the Linux kernel (the first Git repository) and Git [2] itself manage their codes. There's even a git send-email command, that prepare the commits as patches and send them following the using the correct template.
I agree that Git has more of a claim to this than Facebook, but that's kinda like saying a turtle is more of a car than a banana is a car.
Like, yes, it's true. Unlike a banana, turtles have 4 movement-enabling things, they use them to move mostly forward and backwards and not sideways, and other things can ride on them. It's probably more of a car. But it's not a car.
Git has no issue tracker. It's really not a controversial statement. The git community has common practices using something else to work around that, but if that's all you need to say "therefore git has X" then you can claim git has a CI framework because everyone and their dog uses GitHub. Which also has email integrations.
They mentioned them as a counterargument to "Too bad Git lacks a distributed bug tracker".
Which makes it a claim that those tools are git's distributed bug tracker.
A bug tracker and an issue tracker are basically the same term. So that's a claim that git has an issue tracker.
So when you come along and say "Nobody said git has an issue tracker in it." you are either wrong, or you're saying the words "in it" completely change the meaning of the sentence.
If it's the latter, that is a very unhelpful way to communicate, and is definitely splitting hairs. And honestly it's a strawman too because the comment you replied to wasn't using the words "in it". They were saying that you shouldn't say "git has" email. Which is a direct reference to the ancestor comment's claim. It was not hyperbole.
I'm not splitting hairs anywhere. I'm saying that the ancestor comment has the same meaning as "git has an issue tracker". That's not splitting. It's the opposite of splitting.
Email and mailing lists?