The TM site starts shipping their own customized Clover Build. Is that even legal?

You know which site I'm taking about. I am so furious that I am not going to link it.

Are they stealing stuff again? I don't see them releasing the source code for the part which they customized. To me that is blatantly violating the open source license. No matter what license Clover is under, that is just stealing someone hard work and putting your own name above it.

I'm always grateful to the TMx86 site for helping me getting started for my hackintosh journey, then I learnt from here for all the bad things that they did. Given how easy a vanilla build is now, they are not as important now and their practices are harming the Hackintosh Community, where they dumbed down everything into tick boxes without teaching builders proper Hackintosh concept. Making their own solution works without showing how they are doing it, either via source code or documentation, is simply just leeching the community without giving back.

PS: If they indeed did release their source code and I missed it, please post it.

Edit: Typo