I'm this way, and I don't know why. I try to avoid frontend, until I'm more or less forced into it. I can make something functional, but inevitably get grilled about my way of going about it or why I didn't use 2018x style. The fact is, I don't care. I hate every minute of it, and only learn enough to knock it out. I find myself mentally complaining every step of the way. I just don't like how the web as it is is designed, written, or fits together. I wish there was an off switch, as I know i'd be more valuable with these skills, but I'm just mentally unable to accept it.

Web developers are not serious?

That's not my point. I'm saying that there's a difference between the full-stack generalist "web developers" who know HTML/CSS/JS/PHP/Ruby, and software engineers who build complex systems, typically in Java/C#/C++.

There are also people who do both. I started out with JavaScript and PHP and do a lot of React/Angular/Laravel stuff. But I have also worked on complex performance-sensitive business systems written in a mixture of C++ and Rust.

My boss at my last job had done the opposite. Coming from a tradtional compsci C/C++ background (many moons ago), he learnt Angular 2 for a frontend project that required it. Both his C++ and frontend code were among the best at our company.

Saying there aren't good fullstack engineers is like saying multi-instrumentalists aren't good musicians. Sure, the very very best violinists probably don't play other instruments at a high level. But the average multi-instrumentalist (who plays the violin) is a lot better than the average violinist.

That attitude, as if there's no such thing as a complex system on the frontend, is a pox on the industry.

Building complex systems is far from limited to the backend.

Correct. There is a difference. Typically these 2 "types" sell themselves very differently also.

What actually is your point? Reading between the lines, it seems to be:

"Anyone who calls themselves a full-stack developer is garbage - it's just a matter of what side your garbage is on."