sometimes it's something people use when they don't know what to say. like when people see someone and say hi ya alrighttt? they don't really want to know the answer it's just a standard response when you see someone, quirky is the same in that when people can't think of a good way to respond they just say you're quirky and then people are left thinking is that good, bad, what does that even mean etc.
another good example is when trying to list compliments for fat people, one that comes up often is bubbly, which to me is an insult but it's a standard response that hasn't really been properly described so people are left thinking it's at least a response but was it good or bad