Yea yea yea, people can freely use these logos for their project with just changing the color or flip existing project logos, or cutting some part of it but it won't be interesting for a potential investors as they would think the team of a project is not creative enough.
At least if a project does that we know what projects are potential scams in the first place or at least see teams that lacks effort when it comes to their project because it really tells a lot. Aside from them altering the logos onto their projects these logos have other uses as well like what you just have mentioned about coinmarketcap having them, other sites can use it in their projects like exchanges and articles or even a website about crypto. This isn't really meant just for creating more logos as it has other uses like what I have said.
