At that point they're getting negative value out of tabs - people can't set different tab widths and also can't use editors that don't use a width of 8 (or need to reconfigure editors that have a different default). They'd be better off just using spaces.

No, they aren't (but you're free to disagree) and any editor worth their salt can alter how many spaces a tab is displayed with.

I was going to say you're obviously incorrect because in what editor can't you change your tab width? But I realized you are probably talking about the kernel.org project. Is that what you mean? There is an agreement within the Linux kernel project?

Yep, right at the start of the kernel style guide: https://www.kernel.org/doc/Documentation/process/coding-styl...

Wow, didn't remember how inconsistent the Linux coding style is. Or all C basically.

Yes, Linux is the Linux Kernel in this context (in kernel.org)