I don't know either personally, so I'm guessing like most people... I didn't get the idea he's really doing the build due to her. He did make a couple "here's another way to do setups". I guess I took it more as a helpful thought, it wasn't until some of the comments that I even considered it might be taken as a "taking pot shots at her". He even said that it's just another way, and complimented "the other builder" on creative approaches with limited machines/tooling. He never called her out by name or said anything I took as insulting.
Initially, he was just showing some ideas. A viewer gifted him the model kit and asked him to document his build. I assume it was someone that is interested in models and wanted to see his way as well. He makes puzzles and other stuff in his spare time, so why not a model? And if the point is "here's another way, and here's why I think it's better than some other options", it's tough to do that without sounding a little "high and mighty". I suspect that might be a reason he went to other parts the other builder had not done yet. But now it's "doing it in advance of her".
I figure there is always a way to look at things that can cause them to sound offensive, even when no offence was intended. It's even worse if you are dealing with writing, but even in person it can be easy to misunderstand. I try to give the benefit of the doubt. If nothing else, it keeps my blood pressure down.
And try not to discount how tough some technical people find people skills. I work in IT and have worked with a lot of people that really are trying, even if it doesn't seem like it to others. For some people, it can border on a disability. It shouldn't be an excuse to be a jerk, but a little understanding can go a long way.
Just tossing out a possible interpretation. At the end of the day, we all make our own decisions how to look at things. My view is no better than anyone else's.