They have been quite ok[1] about the trademark aspect, but they do have a point about the namespace grab. I'm actually at a point where I do consider opting out of the git integration[2], as the introduction of new entities (project board, pr ...) do make things confusing (or even conflicting) as a series of git sub-commands. I haven't came up with a really satisfying solution though.
Git plugins must have binaries that start with "git-" because that's how they become subcommands. If the binary is called "git-something" for that reason, and it's about the project git anyway, it kind of makes sense to use this as project name.
It's Git's own convention to add subcommands by placing a binary on the $PATH with the prefix `git-`. In this case, the subcommands becomes `git bug ...`.
How would one name this differently?
I tend to think this is more about commercial projects.
[1]: https://marc.info/?l=git&m=153457109619678&w=2
[2]: https://github.com/MichaelMure/git-bug/issues/530