I think what they were doing was a force of habit but it made her feel comfortable.
Was your boyfriend uncomfortable too?
I think so but I bet he will get over it in no time.
It is okay to do things out of habit, but it is not good to do things that make others uncomfortable. People won't want to hang out with her.
I care about her but she needs to gather confidence and grow a backbone. She should learn how to handle this shit herself.
Getting good habits will help you out in the long run and if you do have some bad habits you need to work on them to fix it and make things better.