Junior, Middle and Senior are useless titles

I really don't like them.

In my small company where I work, they call me team leader. Sometimes when I interview frontend devs, that are supposed to be junior, they know more than I do.

At least in theory.

I always see people say that "Hey, Middle should know this and that". Or "Junior should at least know this".

Why? Is Junior in Google and Junior in a small random company are the same skilled devs?

I think instead we should talk only about skills. What company needs is: hey, we have a VueJS project that uses a lot of d3.js. We need a guy who knows that. He might not know algorithms, or have a wide experience in high-load. We just need that guy, call him whatever you want.