I think the root of the problem is more about torture being portrayed at all.
Even if you portray it a the evilest thing, you are still playing with the spectator's bowels and disgust thresholds in ways that cannot bring anything good.
There is room for torture depiction is some niche genres, like horror or sadism (e.g. Salo) but I can't understand how it should come to mainstream media as TV series and take such a big room.
Just like sex and pron: it is ok, but please let it be marginal.
