It's funny because it's redundant.
You could try the classic "Blockland is awesome, forget you!"
Lol.
Is there a way to make him feel like crap and shut up forever?
Does he play Roblox?
If he does, and that's why he doesn't like Blockland, then point out the flaws.
Also, has he even played Blockland before? Because if he hasn't then he has no right to judge it without a proper based view.