What an odd view.
Whenever anyone uses torture to successfully extract information - bad guy or good guy - we are getting the not-so-subtle message that "torture works".
Torture doesn't work. And if you're so habituated to the message that "torture is effective" to the point that you don't even notice torture, well...
But if the bad guy gets good information from torturing the good guy, the viewer thinks "hey, he's an asshole, but torture sure is a thing that works! Maybe the good guy should use it on him!"
>you have a great case for torture being legitimized IF the good guys are using it and are portrayed as heroes for doing so.
You're applying too strict a standard. The article isn't talking about legitimizing torture. It's talking about normalizing it.
In other words, TV isn't necessarily telling us that torture is good. It tells us that it works, and leaves us to fill in the gaps (if it WORKS, we should use it on BAD PEOPLE!)