i mean it's a question of choice, people can just choose wether they want to join the v20 community or just stay on v21...
we're not forcing anybody to join.
their point is;
1. new player goes onto main blockland masterserver
2. because some players are on the v20 masterserver, the overall playercount and servers are lower for that new player
3. "this game is dead" thinks the new player as they notice the low playercount and lack of populated servers
4. they leave blockland
if you have two versions of a game available for a relatively tiny amount of people, splitting them up depending on opinions on which version is better and which to host/play on just makes the game look even more dead, for both masterservers.