It's great in practice, and I would love for all electricity use to be non-renewable, but it's saying that many people in many countries are not allowed to use the software due to something entirely out of their control.
Likely first you'd need some progressive system (e.g.: no less than 80% now, no less than 100% by 2030).
But I disagree with you on that people in many countries would not be allowed to use the software - you would still be able to use the service (i.e., visit garnix.io, have it build things), or even host it yourself in a different country. Yes, countries with more green energy (rather than exclusively cheap energy) would benefit. But the countries with high green/renewable energy aren't even primarily rich ones [0], so I don't feel too bad about that.
Note that this argument only applies to services such as garnix, where you can still use the service (so it would be a bad license for, for example, a text editor).
[0] https://en.wikipedia.org/wiki/List_of_countries_by_renewable...
Which in a way is nice as it enables areas that can't have clean energy (locally) to use clean energy (remotely) via the hosted version, which maybe they otherwise would not, so hopefully acts as an incentive to reward clean energy generation and services wherever they may be (and maybe increase interest in clean energy generation locally if/when that becomes possible in such areas)
This is supposed to say "renewable" rather than "non-renewable"