Giving large scale system design interview questions for a role where someone never has to work with large scale systems would be a weird cargo cult choice.
However, when a job involves working with large scale systems, it's important to understand the bigger picture even if you're never going to be the one designing the entire thing from scratch. Knowing why decisions were made and the context within which you're operating is important for being able to make good decisions.
> I've worked with the Linux kernel, I've written device drivers, I've programed in everything from Fortran to Go, and that's what I want to keep doing. Why put me through this?
If you were applying to a job for Linux kernel development, device driver development, and Fortran then I wouldn't expect your interviewers to ask about large scale distributed web development either. However, if you're applying to a job that involves doing large scale web development, then your experience writing Linux kernel code and device drivers obviously isn't a substitute for understanding these large scale system design questions.