I have mixed feelings here, because on one hand, I actually do see where this guy is coming from. I'm a game design student on a degree course structured around live client briefs and projects for contests (ie, the stuff we make has to work for people outside the university, not just ourselves), and as design lead for the first project of the course, I was fighting with a member of my own team about design decisions throughout the entire project. Dude with zero capacity for empathy spent a considerable amount of energy arguing about how it was a waste of time developing the relationship between the characters in what was explicitly supposed to be a character-driven story. The words "character-driven" were literally in the brief, and right up until the last day he was insisting it was a waste of time focusing on the characters. So I really, really feel the Starfield design lead's frustration on the "stop arguing about shit you know nothing about" front.

On the other hand, I don't feel it's very professional to air this frustration in public. If people don't like Starfield, then they don't like it, and the design lead complaining about it on social media isn't going to change that, nor does it paint Bethesda in a good light. It just makes him look a bit petty, I guess?

I guess it all comes down to whether the product meets expectations. Players are disappointed in Starfield, and even if they don't know why design decisions were made, it doesn't change the fact that the game hasn't achieved what it was meant to achieve. People that spent a lot of money buying it have a right to feel annoyed, and being told "I'm right, you're wrong" by the design lead isn't helpful. And if the project does meet expectations, and it's only a few assholes complaining, then nobody needs to say "I'm right, you're wrong" because the end results speak for themselves. If Starfield had been a massive, widely-loved success, a few armchair devs saying "you should have done X, Y and Z instead" wouldn't be taken seriously.