How is it immoral? Is Google morally obligated to provide you with a way to use their service for free? Google wants YouTube to start making money, and I’d guess the alternative is no more YouTube.
Why is everyone so worked up about a huge company wanting to earn even more money, we know this is how it works, and we always knew this was coming. You tried to cheat the system and they’ve had enough.
I get what you are saying, but you could argue that google is pretty much a monopoly at this point, using their power trying to extract money from customers they could never do if their was any real competition with a similar number of channels and customers.
I think most users see google/youtube as a “the internet”, or a utility as important as power, water and heat. And don’t forget that google already requires users to “pay” for their services with data and ads in other services (maps, search, mail) as well.