I don't think mill as a concept is uninteractive, just how they do it here.
For example, the three Cards I remember one had "every time you draw a Card, the Opponent puts 2 Cards from his library into the graveyard". This is bad on its own because I don't know if it is possible to stop someone's drawing abilities permanently, but it would likely be a damned hard Thing to Counter. Plus, Blue is the big colour for drawing. You cannot interact with or stop this mechanic unless you have a hard Counter destruction Card.
Another Card had "Whenever you or a planeswalker you control gets attacked, the Opponent puts two Cards from his library into the graveyard" which is objectively unfair. Mostly because it absolutely ruins and "Death of a Thousand Cuts" sort of deck while leaving the "Single Monster pushes through" decks or the "Spell Damage Decks" more or less fine. Yes, there are ways to Counter it and I believe this one is a creature, so it is easier to get rid of, but still painful. And once again, a way of doing mill that you cannot interact with much, other than to not attack or use a hard Counter....
The last had "Every time this Card takes damage (From enemy creatures), the Opponent puts that many Cards from his library into the graveyard". This one is painful, because the Player is rewarded for blocking the enemy..... especially bad if the Card survives multiple turns.
Do you see the Problem with These Cards? The Problem is that the entire Situation is under the control of their owner and he has to do very Little to get his effects. He can literally just sit around and let me die slowly.
A better effect would be stuff like "Every time you destroy a creature" or "Every time you attack the enemy Player, that Player", "Every time you Play a creature with cmc of 6 or higher" or even "Every time you return a enemy creature back to his Hand" or a dozen other things that the Opponent can interact with or Counter. Or something that you actually have to do and which is somewhat expensive...
Are there any decks that really screw over mill? Like Black decks with creatures that can be played from the graveyard or something?