When Equestria Girls played the L.A. Film Fest last year, I asked one of the programmers if the choice was made with any kind of acknowledgement of the film's adult fan base. I was told that - at least in the context of its anchoring "Family Day" at the fest, Hasbro preferred not to talk about that.
Well, conversations are starting anyway, as someone supposedly representing Hasbro has now had a product on Zazzle taken down for using the word "Brony" specifically. One, anyway. I was able to find another pretty quickly. When it comes to other fandoms and unlicensed stuff, it also wasn't difficult to find "Trekkie" or "Whovian." A case could be made that those fandom names aren't quite as loaded as "Brony," a term that sometimes comes with some controversy.
That said, this doesn't necessarily mean Hasbro is actively doing anything, or if they are that it's any kind of coherent, consistent new policy. I've posted trailers and clips on YouTube that I had every right to post because they were given to me for that purpose, and had other media companies make claims on them that had no right to do so. I once had an official PR company send me a Marvel clip (the first "Agent Carter" trailer) only to apparently have Disney slap it down and get my account in trouble. Odds are that one employee, or even one hardcore fan, is being overzealous - a person that has never heard of 4chan and doesn't know what kind of mess that can lead to. (Frankly, if 4chan starts trying to assert ownership of the term, Zazzlers may WISH Hasbro were their biggest problem.)
Take a breath, and if you're trying to sell a product aimed at Bronies, consider doing right legally and getting Hasbro's blessing to begin with, or at least being like Tasha Reign and avoiding the use of any term that can be specifically construed as referring to MLP. Brony-Con seems to be still happening last time I checked.
h/t The Mary Sue