Yes, those games have always infringed on intellectual property, and have always been against the rules. Roblox will not take them down unless the IP holder sends a DMCA request to them, but you walk a thin line by having them on the site. A DMCA is the best possible outcome – the IP holder could sue you for damages as well. Having to worry about your game being removed at any given time is also not a good position to be in.
Generally the better option here is to make a game inspired by the IP you like, rather than copying it outright. Note that it has to be sufficiently different for it to not infringe on IP – not just a knockoff with all the names changed.