Roblox seems to be targeted at younger children. Blockland seems to be a bit more general. Or so I think, anyway. Its only natural for two games of the same genre to compete. Just look at CoD and Halo. The same with consoles such as XBox360 and PS3. I'm not taking sides here, but, usually one has more evidence than the other when it comes to superiority, but, we must remember that they are only games. Nearly everyone who has a sibling probably argued over toys when they where younger. I did. This is probably like that; except on the internet. Even the immaturity of young children is there.
This would never happen in Roblox.