I don't really know for sure if that's why or not. Do you have a lot of completions? People might judge you for that, or if your gear isn't up to their specs. It sounds mean but that's what people will do, they check your stats and everything to make sure your good. I would just switch up what LFG thing you use, possibly even use these forums. Just explain your predicament and people will most likely be willing to help you out. People can be massive jerks in this game so it wouldn't be surprising if they are secluding you because you are a girl.