I agree with the reviewer's observation that Veeru and Jay are very ambiguous characters in that they are not rooted to any class or caste or even profession. As such it is hard to to put a “good” or “evil” label on them in the begin. However, through the course of the movie we see the difference between Veeru and Jay whose wrongdoings can be more or less casually brushed off as their cynicism towards social order and conforming to the norms that society presents (ie: having a proper profession), whereas Gabbar Singh's role is more clearly evil, as he a force that is threatening an evident social order. While the reviewer does note that this makes our protagonists more personable and maybe even more relatable to a degree, I wonder if there was more thought behind this particular construction of these two characters.
The “emergency” was at large during the time this movie came out. As such, this provides us with some historical context for this movie. During this time, the masses were growing more and more skeptical about their government, and uprisals were not uncommon. Moreover, close to everybody was being affected by the emergency, and the makers of this movie were no exception. They faced severe opposition with the movie censor board and had to fight tooth and nail to get this movie released the way they wanted. On top of that, they were also facing major budget cuts. I believe all of frustration and aggravation with the government definitely found a place in the characters of Jai and Veeru, especially in their cynicism towards existing social order. This can also be seen in the fact that Gabbar Singh ultimately sees his downfall not in the hands of Police Enforcement but at the hands of vigilante justice, as the reviewer mentions.
Perhaps this is was nudge at the governement's incapability to maintain social order. In the movie, it takes two semi-criminals to put an end to this threat to social order. This duo starts off disturbing this pre-existing order themselves, but perhaps to a forgiveable degree. However, when a larger than life foe that is an obvious threat to said order emerges, the duo conforms to this order by helping to maintain it. At a larger scale, Jai and Veeru might be representative of the Indian population, who are disrupting this new order that is set by a government in whom they do not trust. But by disrupting it they were only hoping to maintain the social order that once existed prior to the emergency.