"who" versus "whom"

I've been spending my day reading the Germany Survival Bible forum from SPIEGEL. I've noticed that there are a number of postings in which "whom" is used in place of "who". One post in particular was a rant about poor education (post #52), in which "whom" was used 5 time, all of them incorrectly:

"There are exceptions of course, but the majority of students in the US graduate while functionally incompetent as individuals (academically speaking-although I haven't met a single high school grad yet whom can give change properly, OR balance a check book)."

These uses are hypercorrections, because they do not occur in the prescriptively grammatically correct location for "whom", which is an object pronoun, whereas "who" is a subject pronoun. The powers that be in American grammar have decided in the last decade or two that "who" is now acceptable in all cases in American English. I'm fine with this, and well served by it, since "whom" is not in the variety of English that I speak. However, I do know the rules for when "whom" should be used according to the style manuals and older instantiations of the English language, thanks to my over-priced education in German, where case systems are still alive and well.

So, here it is:

Who is that? ("who" is the subject of the sentence. German: Wer ist das?)

Whom do you see? ("whom" is the direct object of the sentence. German: Wen siehst du?)

(To) Whom are you giving the book? ("whom" is the indirect object. German: Wem gibst du das Buch?)

With whom are you going? ("whom" is the object of a preposition. German: Mit wem gehst du?)

So, now you know. I'm a descriptive linguist, so for the most part, it's in my ideology that whatever people produce in an oral context under normal circumstances is linguistically valid. However, these forced hypercorrections (I'm sure the writer of post #52 doesn't actually use "whom" naturally in speech) really bother me on a visceral, non-academic level. Obviously, this person is trying to write in a register beyond his/her grasp and is failing at it. Stick to what you know, folks! I think that the most embarrassing thing is to make a glaring error when discussing how stupid other people are, as in post #52! (Better yet is when you specifically try to call someone an idiot in another language and say it incorrectly!)