There are an awful lot of criticisms in that topic regarding Blockland from players who obviously have never played Blockland, nor know the history or have ever experienced the community.
I don't really think you can say that Minecraft has a community, since the game and it's ownerbase is just so massive that you don't know anyone at all. There are too many people to actually form a community whereby you can judge everyone at once.
Not to mention the fact that much of the playerbase is split between various websites/media, such as the minecraft forums, reddit, youtube and more.
On top of that there's no system for a server-list or similar, so chances of you ever playing with a large proportion of the playerbase is tiny.
Roblox has a large community, but it's mostly concentrated within the game itself and the Roblox forums.
There are iffy things about their community, but it's understandable given the particularly young age of the majority of the community.
Blockland has a comparatively small community (although having several tens of thousands of players isn't bad at any rate), but it is entirely concentrated on these forums and within the game.
Having an open serverlist also means everyone can easily join a game with anyone else, so we can actually form a community.
The average age of Blockland Players (or at least when polled on these forums) is about 13-14 years old, with players on ages either side. Overall the community is more mature than the Roblox forums.
So, if anything, Blockland has a tighter knit maturer community, Roblox has a larger yet close community of younger players, and Minecraft has no established community, but rather pockets of communities who are often based around singular subjects, like famous players, servers, mods and gamemodes, rather than Minecraft as a whole.