I don't see the point of the filmmakers.
Nobody will criticize them for a bad film if they don't watch the movie in the intended play speed.
Or am I wrong?
This kind of feature is present in many other devices and services, like our DVD/Blu-Ray Players, YouTube, etc
Who the hell cares if someone watches a movie on slow-mo or slightly faster? Netflix is merely offering the option, they're not forcing the audience to do anything and it will definitely not be playing slower or faster by default.
I'm dismayed that none of the filmmakers see this as the accessibility issue it is. Being able to play at slower speeds can help people with various disabilities. I'd liken this to them being against subtitles.
Broadcast TVs are using this to cram more ads in the same timeslot as you said, which is IMO somewhat unethical, as it alters the experience for everyone.
In Netflix's case, they're merely adding the option to do it, they have absolutely no plan of speeding up or slowing down the content by default.
It's as if Judd Apatow didn't read the article he's referring to.