(fyi: I frequently have students in my classes who tell me: "I love math, I hate English." Is that evidence that math is being taught better than English? I think it's possible.)
A fair amount of the content taught in English classes and covered in composition texts is misleading, confusing, or, in some cases, simply wrong. My favorite example may be the injunction against using the passive voice, which belongs to the simply wrong category.
Passive voice is essential to fulfilling the known-new contract. When you're writing with the known-new contract in mind, and you should pretty much always be writing with the known-new contract in mind,* passive voice isn't just 'OK,' it's required: passive voice is good writing when you need it. Passive voice is so useful that if it didn't exist, somebody would have to invent it.
In my classes, of course, (and this is something the composition texts don't seem to have grokked) I don't have to worry about over-use of passive voice. As far as I can tell, students today haven't done enough academic reading to have noticed that passive voice is a common feature of academic writing, so they don't try to produce imitations of academic writing that feature excessive use of p.v.
As a result, far from having to inveigh against over-use of passive voice, I more or less have to teach students what passive voice is in the context of writing. (Writing as opposed to talking & signage, where everyone knows what p.v. is and uses it all the time. e.g.: Schools will be closed tomorrow...)
But when I'm trying to teach written passive voice using a Word file projected onto a screen, Grammar Check keeps dinging me, so I have to explain to my students that, back in the day, when students did read academic books and did try to imitate academic prose via liberal use of passive voice, writing instructors used to tell their students not to use passive voice, and that's where Microsoft Word got the idea from. Microsoft Word thinks passive voice is bad because George Orwell and Strunk & White thought passive voice was bad (my students have never heard of George Orwell or Strunk & White), and college students used to use way too much passive voice, but .... passive voice is not bad, and Microsoft Word is wrong. They should think about the known-new contract and use passive voice as needed.
Speaking of Microsoft, this was the first semester I 'infused' technology into my teaching, by which I mean I figured out how to use the laptop-projector set-up so I could project sentences and paragraphs onto the screen up front. When the class talked about passive voice, Microsoft's objections actually got to be pretty funny. We'd be cruising along, writing our sentences and making them cohere, and DING! Word would put a green squiggle under a passive voice construction.
Then I'd say, "Microsoft Word doesn't want you to use passive voice."