1: English is required for lots of things, sure. ENGLISH however, as in, the subject, is just pointless word salad as far as I am aware.
I am not sure what you are saying here. Learning to communicate in English is critical in today's society. That means understanding how to speak, write and read (and more importantly understand what you read.) Other languages are good to know, but the most important skill that has to be taught in school is to communicate well in one. So the underlying goal is good communication; English is just the way most of us learn to do that. The name of the course in most schools that teaches one to communicate in English is English.
Of course, as before, there are good and bad teachers.
2: sure. But it is taught wrongly in most cases.
Again, there are good and bad teachers.
4: Okay. But they would just find out about it naturally otherwise, probably by overhearing people discuss it. Also, I would say that most people being taught about sex in health class already know about it.
Oh, you'd be amazed. My mother was a writing teacher in a high school, and she overheard some pretty amazing misunderstandings from her (and her colleague's) students.
"It would be my first time so I wouldn't get pregnant, because of the blood thing."
"You can't get pregnant when you have sex in that position."
"When guys have an orgasm, they pee a little - that's what comes out."
It is true that education might make one better at some things, but I would say that it is more about compliance and slavery than learning, and that people don't really understand what they are doing, and are just reciting what they don't have a clue about in ways which sound really intelligent in school.
I would argue that you can teach math that way to some people and they will come away knowing how it works. You can teach math that way to other people and all they will come away with is being able to recite it and being able to do the problems on tests.
The first set of people is better off. But both come away being able to do basic math.
It's not a joke that the internet is good for learning. It is a wild west of information, which one can sift through selectively to find what one needs to know, cutting out the drivel and pointlessness.
The Internet is a great tool if you know how to use it. But it is 99.9% misinformation, drivel and pointless nonsense - and it is designed to give you that stuff FIRST.
I often use it to look up academic papers, for example. You have to make a conscious choice to do that, though, and generally use a specific search term to ensure you get (mostly) academic material.
