Using open source code in compliance with the license assigned by the author is entirely reasonable and good. I really don't get the "Coldcard side" of this argument.
Good read and more evidence that #[0] is on the wrong side of this ridiculous drama.
https://www.zherbert.com/an-open-letter-to-nvk-and-coldcard/
Discussion
What is the point of a FOSS license if you don't want people to be able to use your code for their own purposes? FOSS is more than marketing.