Do I have a right to be annoyed about who my gf hangs out with?

Yes, and not just annoyed, you have every right to be concerned about her and her safety. You have higher standards and not only that they are higher, they are correct insofar as they are decent and upstanding. Hold to those standards and have the courage to encourage her to aspire to the same standards. It has nothing to do with who she hangs out with, it has to do with her sense of self, her sense of worth, her sense of dignity that you want to help develop in her. Do it from the point of view of concern and care for her well being. Say that if she hangs out with people like that, she might end up getting hurt and if she decides to do that, then you will not be around to help her out if something does happen. That way she has a choice, live well with you or continue on a path of baser standards with the crowd. If she won't listen, then she is on her own because you will not stand by and wait for something bad to happen, because _you care too much about her to let her expose herself to those risks_.