Because they have a rabid fanbase that'll fight for their side tooth and nail.
This is the exact same thing that happened with Turbine (LOTRO) a year or two ago. Turbine came in and swept through March Mayhem almost with ease (even people voting against them in spite didn't stop them) because their fans came in and voted for them. They had a lot of fans.
This pissed people off, and then we don't really hear negativity, but frustration. Don't worry, other companies will take Mojang's place, and people can get pissed off about MM next year.
This is the exact same thing that happened with Turbine (LOTRO) a year or two ago. Turbine came in and swept through March Mayhem almost with ease (even people voting against them in spite didn't stop them) because their fans came in and voted for them. They had a lot of fans.
This pissed people off, and then we don't really hear negativity, but frustration. Don't worry, other companies will take Mojang's place, and people can get pissed off about MM next year.