Edit: I misread the non-commercial bit. Regardless, I making it opt-in by default is scummy, imho.
If you have a subscription then it’s opt-in.
That seems perfectly reasonable.
Again, this is for the people using JetBrains IDEs for _free_. You can pay for a subscription and it becomes opt-in. I think it's completely reasonable for it to be opt-out or even required for the free product. Giving non-paying people a choice is a step above what I feel they are required to do (morally, ethically, etc).
Not sure what I'm missing with spacemacs + LSP compared to vscode. (Spac)emacs does not train on my data. I don't pay for spacemacs.
Visual Studio still would still be kept on mantainance mode for 10 to 20 years because of there's so much critical enterprise infrastructure that depends on it.