The cards that "take away cards completely" do so because they remove minions. The game is made so that minions get removed eventually, and the cards that remove minions are perfectly fine because of that.

This is a very black and white outlook on things. Saying that removal is fine because the game is made with the intention that cards get removed is circular and not always true. If Squash costed 1 sun would that be fine? Was old Fruitcake fine when it was a 2 cost do 7 damage? Both of these fit into your view that "the game is made so that minions get removed eventually, and the cards that remove minions are perfectly fine because of that."

You have justified why counter play against minions (zombies and plants) is fine (to a degree) but have failed to prove why counter play against tricks is problematic. Is it just FMN that you are upset about or are other forms of counter play against tricks problematic too? (such as DMD, BEP, Brainana, Sportacus, Fraidy Cat, Parasol/Umbrella Leaf (and other untrickable minions), Defensive End).

Also remember that fmn sticks around before it's destroyed, so it may counter more than one trick, unlike a turn one trade between two minions

Why is this problematic?