I have friends who love Homestuck. I never really got into it, but I did make a Feferi cosplay minus the gray body paint for a get-together with my friends. I had no knowledge of the series, but they were very enthusiastic to talk to me about it. From an outside view, I think that because it is not an anime, people look down on it. At first, I was intimidated by a bunch of gray people with horns walking around, but once you get to know a few of them, they're really nice people. They are normal people, just showing their love for their fandom.
Being a gathering organizer for popular series, I think any series that becomes popular and has more fans and cosplayers, gets hated on, just for being popular. Cosplayers too, often get a little excited seeing so may other cosplayers that they forget a bit of common sense now and then. Haters just find the faults and make it into a big deal.
Also, the convention scene has changed a lot and is more about going for merchandise, cosplay, and photos rather than community and conversing with others. The first year I went, no one talked to me except for my friends and people asking for pictures even though I was cosplaying from Hetalia. So don't feel like you are getting ignored, that's just how the convention scene is now. You do meet the occasional open people though, others might just be awkward and shy, who knows.