Anyone else with this obsession here? :P
It was absolutely massive in internet nerd culture around 2011-2012 (and is still pretty big now) so certainly it picked up a lot of those kinds of personalities that sometimes coincide(?) with the autistic spectrum.
As for me I couldn't really be more "Brony" if I tried. Always in forums about it, huge collection of figures, plushies, t-shirts, go to conventions, etc. If there's a flat surface there's a pony on it, if it's a vertical surface then a pony sticker. And as anyone who knows the show/characters would spot with the username, there's usually some indication of my interest somewhere.
I really love how much creativity there is in its community. So many brilliant fanmade videos on Youtube. So many good cosplays at conventions. Etc. There are um, infamously less tasteful corners (don't ask) but I really think they're something of a minority.
Generally speaking when I get into things I get into them really heavily and for years.