It's not portrayed unilaterally at all. There are many POVs in the series on torture.

Many torture scenes (one driving mad a sister with horror scenes in a VR ter'angreal, another is letting Ronde Macura's imagination run wild, Fain with his victims, Sevanna/Therava and her slaves, Cabriana, Moghedien and SH, Moghedien vs. Nynaeve, Mesaana vs. Alviarin, Aran'gar vs. Sheriam, the mindtrapped Cyndane vs. Moridin) produced results (some times quite mitigated, eg: the fact Sheriam was broken was heavily noticed around her)

But there's plenty of scenes in which torture is depicted as something totally unreliable (several mentions, even some by WC characters, that the Questionners' methods produce tons of false confessions. Some of the same is said about the Seanchan Seekers), or negatively as something unacceptable for leaders to use. Elayne has several reflections on this through the series, as Andor is one of the places where it's been made illegal and she was in a few situations where she had to make a personal call on using it herself or look away as someone else did it. The fact the HL used torture, which Rand put an end to, was shown as repellent through the eyes of some characters. Etc. Of course there was Semirhage, on which some variations on classic torture means produced no results. And Egwene's, whose "penances" had turned into torture to make her break, which failed.

RJ really included a wide variety of opinions on torture, but if you notice the trend, the vast majority of the episodes of "justification" of torture (by their results or from the characters taking a political/moral stance on it) in the series were tied to the Shadow or characters considered morally depraved/evil.. Fain, Questionners, Seekers, Elaida, Sevanna, Forsaken. The BA who captured Rand, Egwene's sul'dam and so on). Just a few of the "good guys" got anything of value from using it, and those showed massive restrain (mind games rather than physical pain etc.)

There are also quite a few scenes with "good" Aiel, where the issue is discussed and Aiel say it's always left to older and experienced people, because young warriors tend to lose themselves in it, and get only dross from the captives.

Nynaeve is another who when she inflicted pain to prisoners felt soiled and disgusted with herself.

Amathera on whom torture and other humiliations were used is a totally broken woman. RJ used her to draw sympathy for the victims, and to show how terrible using it was.

It's also during the storyline in which she gave in and started using (or ordering) punishments that fell to torture (severe beatings, deprivations), cruelty and finally a full attack on Egwene that Elaida went from harsh/cruel to bordering insanity and "lost it".

It's above all hard to forget how Jordan used the theme of torture/cruelty in an extremely negative light in the episode that finally made Perrin hate what he was becoming so much he finally threw his axe away, and how Aram was shocked and that's when he started visiting Masema and got convinced Perrin was a DF. It was during the same book that Perrin started saying he didn't care the Seanchan were DF, he'd made a deal with the Shadow if it's what it took to save Faile, or to say if the LB started, he would turn away from his duty if Faile had not yet been rescued. Perrin was a in a very dark place, and RJ made his act of torture the pinnacle of that, even compare it to Perrin turning into an animal while suggesting that wasn't fair to the wolves, that themselves are never shown as cruel.

It's also had to forget how he made Rand take a moral anti-torture stance early in the series (one of his first political decisions in Tear) and how this never wavered and even become one of the last things Rand held to fervently even in his phase of madness/darkness in TGS (people who think it's all about Semirhage being a woman have forgotten that Rand has rejected torture of anyone and held to his moral principles even against a captured Forsaken who herself has tortured countless people.)

As I said, there's really a rich crop of diverging opinions shown in the series on this topic, but RJ's dominant stance on the issue has tended to lean more on "it might exceptionally produce results if you show much restraint (Macura, Talene etc.) and follow rules and put safeguards in place (the BA hunters, the AS in general) or just frighten/threaten, otherwise torture is a very slippery path to losing "your soul"/crossing the line by using means the Light shouldn't use to fight the Shadow, because it's as bad as the Shadow (the whole Shadar Logoth theme and its variations, like Sevanna, Masema etc.).