Um, what? You have linked to an explanation of why it's not fine. This mistake is getting more and more common, even among educated people. It's quite embarrassing/funny because it stems from a belief that "I" is inherently more "educated", and the result sounds anything but. I know us English speakers can't speak any non-English languages, in contrast to the rest of the educated world, but it's really not too much to ask for us to be able to comprehend the concept of subject of a sentence. Our parents' and grandparents' generations managed it fine, in fact would have been mortified to make a mistake like this.
This is actually one of my fury triggers whenever the spouse is watching trashy reality shows on television.
I recall from my early public education that my peers and I were all taught incorrectly. They told me and my classmates to use "I" rather than "me" in all compound nouns, rather than to use the correct pronoun. This is burned in my memory. It happened. Don't try to gaslight it. At least one teacher taught every last one of their students the wrong grammar.
For instance, this would be correct. "She and I [1] went to the theater, and the ticket-agent told her and me [2] that matinee prices ended at 4 PM." Countless fools would put "her and I" in position [2], sparking a righteous, impotent rage in my soul.
Also, it's "I know we English speakers can't speak...". Try taking out the descriptive. "I know us can't speak..." versus "I know we can't speak..." Select the correct pronoun, then put the descriptor back in.
Haha fair enough! And thanks for pointing out that it's actually been propagated by school teachers sometimes. I definitely deserve to be corrected publicly on the "us English speakers" thing. I could try to defend myself on the basis that I was deliberately affecting a more popular mode of speaking at that point, at the expense of correctness, but the truth is I've never said or written "we X doers". I'll bear it in mind for the future!
https://en.oxforddictionaries.com/usage/i-or-me