indeed you are wrong, makerworld does not hold any rights to your work, it’s still your work, what you agree to is that you only host / publish the designs on the makerworld platform and not on any others (printables, makeronline, cults, patreon, etc)
the standard digital license governs the use of how users can interact with your work, the reason that makerworld enforces it for their own benefit, is that it does not allow reshare of the digital files, which means a user cannot post your work on other platforms, which some of the CC licenses allow for
as long as you’re not distributing the design files themselves elsewhere you are complying with the exclusive rules, and to be clear allowing people to sell prints under a commercial license has nothing to do with the exclusive rules, it would be infringing if you were allowing them to sell the STLs for example