Thats undecided by the courts. Everyone is training using other people's data right now though, and very few companies are even being sued (let alone have finished the multi-year process to actually be punished for it).
> Or does that mean I should close off all of my creations
When you put something out there, you should expect that other people are going to use those creations. Almost certainly in many ways that you don't approve over.
Don't release something publicly if you don't want other people to use it.
> but I do have a problem
Your anger isn't particularly useful. What are you going to do about it? This particular proof of concept model was made with 1 single GPU running for 2 weeks. You can't stop that.
> It's just as I would have taken a 3d model static mesh, apply some blend on it and call it my own.
Something that I am sure many people are doing all the time, already. Transforming and using other people's content is as old as the internet. AI does little to change that.