Except that their servers are constantly pulling large numbers of people. How can the content they host be that bad? Just because you personally don't like them?
Considering the fact that a quick forum search of either of those people or their servers immediately brings up literally
dozens of drama topics, that should tell anyone not familiar with them all they need to know.
Large playerbase =/= Quality server. From personally playing this game for over 6 years I can testify that the stufftiest servers have always tended to get the most people, sad as it is.
If you actually frequented their servers (I don't know how much you actually play Blockland but I'm assuming it's very little, considering how unaware you seem of the stuff that goes on with Tezuni and Raven's servers), you'd know exactly what I'm talking about without any explanation needed.
There are tens of millions of feral children and adolescent sperglords who love the latest MLG Call of Duty Advanced Modern Ghost Ops Warfare bullstuff games, that are literally all the same exact unimaginative generic FPS stuff just repackaged and sold every year for steep prices, and rife with cheating and abuse, but that doesn't mean they're good games just because lots of people like them.