Someone explain to me how tags work or else I'm gonna have a heart attack.

I was originally under the impression that you just pick a fandom, and then once you pick a character they get that fandom tag added to their profile whatchamacallit. Thing is, I made two csm bots and vividly remember setting them on private. A couple days passed, I got bored of my current scenario and went to make a new one. Then when I pulled up my character I saw they had a peculiar tag called "chainsaw man omegaverse" with them. and listen i dont wanna overreact, BUT CHAINSAW MAN OMEGAVERSE???? i did NOT put bro on fucking CHAINSAW MAN OMEGAVERSE???? are my characters just not on private or am i so ridiculously wrong about how tags work??? if they aren't private i might end it all.