This thread got me thinking about "quirky" people - I was in a group in college that was sort of the definition of "quirky," and I noticed some things.
Everyone in the group prided themselves on being openly, proudly quirky, and enjoyed weird hobbies, frequently as a group. But I noticed that there were three types within the group when it came to dating: Those who were quirky, enjoyed being quirky, and sought out fellow quirky people to date; those who were quirky, enjoyed being quirky, flaunted their eccentricities, but thought that all of the other similarly quirky people in the group were just too weird to date; and those who were enjoyed the quirkiness within the group but also enjoyed other hobbies and could "assimilate" and date people outside the group.
The thing is, the first and third groups were happy, because they had the self-awareness to either enjoy similarly "weird" partners or to see when they were better served enjoying the hobby but not making it their life. It was the ones who insisted on being "weird" but refused to date "weird" that were miserable, all the time.
In other words, I don't think there's anything wrong with being weird, but you have to have self-awareness about it. You have to either choose to date equally weird people, or choose to not make it a full-time lifestyle.
Edited to add the point, because I forget sometimes: I don't know if any of that would help your friend, but if she's so proud of being eccentric, maybe there's a way to communicate something like that to her without being judgmental. That there's nothing wrong with quirk, but you have to decide what you want to do with it.