Despite the efforts of some members of the fandom, bronies are seen as a bunch of bigoted rape-apologists. It's not just that they like a children's show, it's that they usurp a safe space for young girls and distort it into a fetishistic and toxic environment.
Most media coverage of bronies has been vehemently anti-brony, with the exception of a few positive articles. These have mostly been written in conjunction with local brony conventions and feature interviews with bronies from the region. Most of the time, these articles have a tone that is more instinctual than supportive. The language used in these articles is teeming with stereotypes that are clearly intended to be offensive. Bronies are "effeminate" and "creepy" (Collins 2012), while they are also "surprisingly harmless" and "harmless in their actions" (Fallon 2014).
The media's negative depiction of bronies is fueled by the fact that it seems to be difficult for many people to accept grown men enjoying media content made for young girls. The majority of people seem to find this very unsettling, and it seems as though most feel the need to demonize the community in order to justify their discomfort.
Those who would like to defend bronies tend to use the argument that every fandom has its toxic subsets. This is true, but it doesn't excuse the fact that bronies have had to deal with death and rape threats over their hobby, multiple blogs dedicated solely to documenting sexism in their community, and mass outcry over sexualizing a children's cartoon.