Let me get a trial, Siva. My case is as follows.
We don't enjoy movies because they are perfect. We enjoy them when some works out so well that we forget (or at least forgive) all that's off.
The reason that scene singularly stands out to me is because of the gender twist on the usual trope of the male gaze and the femme fatale utilising the male gaze. We don't even see that trope as an issue. But when a hero has to deal with the same objectification that is so usual and expected of the heroine, that's subversive gold.
And that's what I loved about the scene. That Nani had to undo his two buttons and he feels embarrassed about it. The entire scene is a hoot because he has to endure what he thought was very okay for the heroine to endure.
Among the things I am socially conscious about, gender equality ranks very high. Possibly because of the strong (even if flawed) women in my family. They are a class apart. As I go further, I worry about caste, education, political and economic justice, and such. Gay rights are quite low on my priority list.
Admittedly, mine is a low bar for representation of gays in cinema. Even so, I can still address your concerns with the scene.
Firstly, Vennela Kishore isn't necessarily being effeminate in the scene. He is merely horny. When he is not being horny he behaves very much like your regular bloke. This is in sharp contrast with Telugu cinema's usual conflation of gays and transgenders as the "Thedagaadu" in films such as Pilla Zamindar or Gundejaari Gallanthayyinde.
Moving on, the gay character isn't going after every man in his vicinity. He has a thing for the electrician, yes, but he doesn't begin to desire Nani right off the bat. That dynamic occurs only when Nani casually quips "kaani ammayilani evaru premistharu?". Upto that point, Vennela Kishore is the standard snarky bank security employee.
And I am not sure if my memory serves me right, but I believe he doesn't lech after Karthikeya, easily the most attractive person in the entire film. That was such low hanging fruit and letting go of a cheap joke there shows that Vikram Kumar wasn't trying to be cheap.
I mean, the film doesn't make fun of gay characters. It makes fun with a gay character.
Of course, I could be wrong. You be the judge.
GANG LEADER (2019) REVIEW
Five wronged women (well, four wronged women and one wronged little cherub) seeking revenge, enlist the services of a plagiaristic writer (Nani). This completely clueless motley group - um, gang - is to find the man responsible for their bereavement and kill him. As far as revenge plots go, this one is standard, but quirky, and begins enjoyably well. In fact, the first yawn sets in only after the two hour mark. Then the yawns start coming in like wedding invitations during Sravana maasam. Indeed, the last half hour had people stretching their limbs like they were warming up for a post-show yog....