I'm sorry but this is not evidence that Tezuni is plagiarizing work here. The word 'by' in this context means that Tezuni is hosting it. For example, "Marty's Muffin Shop by Godaddy.com".
"martys muffin shop by godaddy.com"
"tezunis rising lava by tezuni.com"
this is the scenario i see 90% of the server population interpreting:
"oh, these servers are hosted by a guy named tezuni, and it says made by tezuni.com. this guy must own that website, so this guy must have made rising lava!"
i mean tezunis servers arent necessarily known for having the smartest userbase, so i know most of them arent interpreting this the way you are
This is an inherent risk regardless of how many labels and watermarks you plaster onto something. I've hosted tons of mods that literally advertise in the welcome message, and people will still ask me whether I've created them. It's not the host's responsibility to make sure that everyone is aware of who made all the content on the server.
and while this is a valid point, it still wouldnt hurt to have some mention some where. sure it isnt the hosts responsibility to make sure people know who made what, but i mean this just boils down to being fair