If you don't care, as you claim, then just use the new word. It isn't hard. You wouldn't be fired for using the word blacklist. At most, someone would consider

If you don't care, as you claim, then just use the new word. It isn't hard. You wouldn't be fired for using the word blacklist. At most, someone would consider gently suggesting using "blocklist" or something like that. If you continued to use blacklist, apparently to demonstrate some sort of thesis, you would eventually be asked to articulate this thesis. After being unable to do so without sounding like a petulant child, your coworkers might think less of you and maybe you would not be promoted or moved to a different team or something.