It would absolutely bother me less if my partner met a friend and said "you know what, not for me" because at least that shows that they made an effort to get to know the people close to me. They don't have to like my friends, so long as they can behave civilly if the occasion calls for it.

If you have some trauma behind certain behaviors, work on that with a therapist. Trying to avoid it instead of learning to deal with it doesn't make things any better.

The example of the friend behaving in a creepy manner doesn't really apply here. You're assuming that this person is going to do something based on your interactions with completely different people. If you want your boundaries to be known before hand, ask your partner to tell their friend in advance so it doesn't come up.