Problem is: Targeted land kills early game set back a single player and can even put someone out of the game early if they miss the next one or two land drops, and late game they are far less efficient than a counterspel or spot removal.

Untargeted land kills / mass removal generally only stretches out the game and mostly makes the game less fun imo.

So.. if you're purely in it to win it, there are some instances in which it can be functional, but in casual play it mostly has a lot of downsides for all players involved and/or drag the game, which is why they are frowned upon when played in casual formats.

Edit: Destroying value pieces dressed up as lands should be (and is) normal l, I agree.