Yeah, it feels to me like there's some other reason they dislike VLC that they're not telling. Does it compete with their own media player or something? Did the creator of VLC date a Unity exec's ex?
VLC violates the DMCA, as well as includes patented MPEG style codecs, the end users of which (under a mostly USA-enforced legal framework ?) are supposed to pay royalties to patent owners, which I presume they almost never do (?) :
https://wiki.videolan.org/Frequently_Asked_Questions/
So it might be possible that someone from the USA decided to strongarm Unity ?