They aren’t sucking anything up. They don’t care what you think. Grammar nazis sound like the grownups in Peanuts to the people around them, just a bunch of “whawhawha”. Nobody’s trashed nothing, it’s just how things go. The people of the 19th century would be just as appalled at your grammar as you are at modern grammar, the only difference is you have a Strunk and White to say you’re right.
Strunk and White is a manual of style, not a grammar. That you don’t grasp this distinction and somehow regard S&W as the apex of English shows that you are really out of your league in this conversation.
I really doubt you know enough about English grammar to opine that mine would not have been recognized as standard 150 years ago.
Can you foresee a time when “those who don’t care” have pushed their version of the language to the point that they can’t communicate outside their limited circle?
It happens to degrees between generations and regions without severely mutilating the language, but you can also see how, taken to an extreme (aka Ebonics), it can make communication between groups of people nearly impossible even though they are using the same language.
There are many reasons to have standards, whether it be threaded fasteners, code libraries or English grammar, and they don’t necessarily indicate some sort of superiority complex by those promoting them.
This “modern grammar” you reference is but a cover term for ignorance. And you damn well know it.