I counterspell/destroy/exile/edict your commander. Over and over and over. To the point you now have such a high commander tax, that you can't cast your commander from the command zone. Do you have other cards in your deck that rip the commander from the command zone to your hand OR do you fold?
There's a big difference between 'I play one spell to tuck your commander, I hope you didn't need him' and 'I play half a dozen spells to keep knocking him back in the command zone, I hope you didn't need him'. In the second case, at least it took a concentrated effort, rather than a single blue spell.
Tuck was never a guarenteed answer and was just another option for opponents to answer a commander. Treachery and gilded drake effects can also deal with a commander in ways that some decks can't react to, yet these cards will never be banned. And if the opponent running those theft effects decides to pack a few counter spells, then a stolen commander can be impossible to get back, while tucked commander can still be found.
Every deck will run at least some removal, but not every deck can run creature tutors. In other words, just aboute very deck can deal with theft effects, but not all decks can deal with tuck effects. In fact, metas that prioritize interesting deck-building over consistency and linearity are almost guaranteed to have very few to no tutors.
A better comparison for the effect of tucking is imprisoned in the moon. It's an effect that most decks can't deal with at all, and that'll likely see a commander taken out permanently.
A couple of years back, when a commander became the target of a spell that'd put them somewhere into your library (instead of destroying them or exiling them or whatever) you wouldn't get the choice to put them into the command zone instead. So, for example, if your commander got hit with spell crumple as you cast them, then they'd go to the bottom of your library, and chances where you'd not get the chance to play them again that game.
I disagree. You should not be punished for building a deck around a commander in a game-mode where the commander is the main unique selling point. Having 'tuck' effects effectively be 'return target commander to the command zone' is strong enough imo.
My problem with tucking also isn't 'white/blue do it better' but 'it makes the game less fun'. At least most mass land destruction (that i'm aware of) is at least somewhat symmetrically, but among my play-group we've also agreed not to run any of the big land destruction cards.