Roblox is inspiring people to rip things off. To plagerize. Is this not concerning to you? No, because you're a roblox shill.
roblox is encouraging people to use the content creation platform to create fun games that people want to play. if people want to play murder mystery in roblox, and someone successfully fulfills that demand, they are rewarded for it. nobody on roblox becomes successful for lack of effort or interest, you still have to create an experience that people enjoy playing. people implementing design elements and ideas from other games is nothing new and it isn't plagiarism (you can't/don't really copyright or patent a game design concept anyways). this is called iteration, and it helps us move forward. the majority of gamemodes in blockland and gmod (and really, most games in a general sense) are based on designs that already exist. speedkart, any TDM, mafia madness or other games in the same vein, jail escape, gmod's TTT and murder, prop hunt, etc. are all implementations of existing ideas in a new environment, and people play them and enjoy them because they are fun to play, and people make them because they enjoy those experiences and want to bring them into an environment they enjoy working with, probably taking the opportunity to also add their own spin to make it theirs.
creating an enjoyable experience from square one is not easy, and people never do it. practically any game you can think of is based on things that came before it in some way, whether consciously done or not, because that's how any form of creative work is produced, and how a medium progresses as time moves onward.