I declare this distinction unofficially dead. 300 years ago, choosing the wrong form could get you into disrepute, forever ending one’s status as a lady or gentleman. Today, knowing when to use one or the other marks a person as a word watcher.
Imagine asking your child “Whom did you play with at school today?” (This usage is alleged to be correct.) If you can’t imagine teaching this to your children, it’s moribund if it isn’t already dead.
Even the most staunch “defender of language” will admit that questions just aren’t begun with whom. William Safire, a more sober advisor of linguistics, suggests “When faced with a choice between the pedantic and the incorrect, recast the sentence”.
The “correct” usage, by the way, has a simple rule. Practice a different version of the sentence. If you would say he, use who and you, but if you would say him, use whom and ye. Who and you and he are subject pronouns, while whom and ye and him are object pronouns. You would say “you love him” not “you love he” and so the question ought to be “whom do you love?” That would have made for a disappointing blues song, though.
Finally, let’s get to the meat. Whom is dead, but how can we really tell? Native English speakers don’t use it. Like “Ebonics,” whom is simply not Standard English. Languages evolve, while some constructions (ye, whom, though sayeth, verb last as in “with this ring I thee wed”) die, and others are born.
No native speaker says “I running” or “John Mary kissed” or “who was playing with John and?” Even 3 year olds avoid these errors most of the time, because these really are errors. Refusing to split one’s infinitives may be a sign of education, but it’s not a part of the English language. If it were a fundamental part of the language, nobody would have to explain it to you, because you’d already know and obey it.