It's easy to point and laugh from the outside, same as with any fandom. There is a surprising amount of resistance to the idea that an adult can be into a cartoon, as if the medium itself is below consideration. Bronies have it doubly bad as the IP was and is aimed at girls and the idea that a male could enjoy the show too is anathema to traditional Western masculinity. (A female who is into Star Wars or GI Joe is 'cool', but a male who likes MLP-FiM is a weirdo).
I'll argue that one of the reasons it got so popular, its because Faust didn't want to focus the series to an exclusively girl audience. At least when it comes to the first two seasons, you can find a bit for everyone. This can be seen very strongly at the beginning of the 3rd season with the introduction of Sombra. Who by all accounts was supposed to be the main villain
and bring a bit of darkness to the MLP universe. The Sauron inspiration is VERY strong, and I believe that this scared Hasbro as they felt they where losing control over the franchise.
And I speculate that is the reason Hasbro decided to terminate Lauren Faust, or maybe Faust decided to leave since clearly Hasbro had other plans for the series. What a shame.
I believe it is WAY overdue that western entertainment stop treating children as if they where stupid or could not cope with complicated situations. Or to see them as nothing but walking purses.
And to prove my statement, I will just point out that one of the most watched series by today's kids is My hero Academia.
Allow me to give you a sample of the show.
Yeah, kids are watching this, and so far none has fallen into some kind of trauma.