There are thousands of engineers (at least) who use it or its equivalent every day. Just because they’ve built abstractions that allow you to ignore it, doesn’t mean nobody has to deal with it anymore.
But that's identical to what he's saying; he's not saying no one has to deal with mutable memory. Just that most developers who need concurrency shouldn't have to. Same as registers, GOTO, etc.
That's not what they said. They said "nothing is cool about a tutorial on creation of threads", and that the cool thing is "achieving concurrency without threads/race conditions/shared memory" which ironically is only enabled by all the engineers who spend their time working on and maintaining those "uncool" things.
If they don't need to use threads, then good for them. But to dismiss threads and learning material about threads as "uncool" is just silly. The thing that enables that misunderstanding is all the work that's done on them in the first place.