If someone goes “You can ONLY use the words ‘butch’ and ‘femme’ EXACTLY the way they were used in the US gay and leabian bar scene 50 years ago.”

That person is almost certainly trying to restore a fictional past when lesbian spaces did not have bisexual people. (NEVER HAPPENED)

Fuck that person and their authoritarian approach to identity. Terms are ever-changing. Words have never meant just one thing. You are okay. Use the words that you feel connected to.