I repeat: I have deep respect for homebrew developers and that obviously includes you! That doesn't change the fact, that I will decide against installing/running DRM-infected software (for whatever positive, understandable, justified... reasons DRM is used) on my machines.
I can do pretty good without software containing DRM (and since I stopped acquiring such I feel much better). If the majority can enjoy things with DRM (or because the DRM is actually good for the game or whatever) this is fine for me as well.
There's no penalty to play CTGP-7 offline, the "DRM" is strictly for online and solely to prevent cheating of any kind. If you were to play online and everyone else in your lobby is cheating, wouldn't you question the existance of this online mode? That's why these restrictions are applied, to ensure you cannot cheat, even by the simplest mean, that is opening the Rosalina menu, as Pablo explained.
For the false locking of the menu outside of online mode / MKChannel, that is a bug and shall be fixed eventually, but don't put this up as "omg PabloMK7 is a dictator, he disabled my menu!"
As i'm reading from other threads of yours, I'm not sure if Ondrashek06 is trolling at this point.
This is imposing unnecessary DRM. Homebrew was meant to relieve whatever shitty DRM Nintendo implemented. That doesn't mean others can implement their own DRM and defeat the purpose of homebrew...
This is not the only "purpose" of Homebrew, in fact, it's not even a thing it does, except removing the region lock. Homebrew is not for piracy and cheating either, it's merely a side-effect of allowing unauthorized code to run and such developers creating solutions for these subjects. Homebrew literally is that: allowing anyone to run any code on the system.
As Pablo suggested, just get rid of the mod and stop whining about it; what you're trying to shove Pablo in his butt is entirely against the integrity of the mod in the online modes. I legit only play Mario Kart 7 through CTGP-7 as I can be sure that I cannot cheat and the mod's anti-cheat working even better than Nintendo's garbage security, which even feels non-existant thanks to the advanced cheats hackers use nowadays.
Oh: If you really care that something has a DRM of a kind and immediately refuse to use it, then you pretty much cannot play anything nowadays. I wish you good luck with that philosophy, seeing how Denuvo, for example, just launched on Switch. ofc terrible example, but you still get what I mean: DRM is everywhere, even in unsuspecting minor things.