mojang is owned by microsoft, but its still a different company. Like how Porsche are owned by Volkswagen, Mojang is owned by Microsoft.
There have been so many threads about this lately :P anywho, it's sad, right now I'm really debating whether this is stupid or fair.
I think it's fair. I mean, the EULA has been there the whole time, and people are expected to follow it. But meh, I think it's the server owner's faults for not following it in the first place.
Because Mineplex ranks don't give you any kits or anything. It is in game currency called gems and you can get those by playing games and stuff like that...But wait their ranks give you tons of gems. Basically Mineplex is pay to win and they are just hiding it.