Why is ledging frowned uopn?

Im a new player (just started this month) and I always thought the use of walls and ledges in the game is done really nicely, and in low rep matches everyone makes use of them. But as i see videos of high rep matches or just familiarize myself with the culture i found out ledging is actually frowned upon and i don't get it. Its not like Its an op move or character that gives an unfair advantage or something, its just a feature of the game everyone can take advantage of at the moment. Plus, the added stress of fighting near a ledge is actually kind of fun, like people complain about for honor not being "realistic" enough but do people expect just dry matches left and right? someone please explain.