Am Indian, I'll try and explain this crap mindset in the Indian context.

Why is queer people existing “dishonorable”???

Queer people are considered disgusting + a Strong Community sense to the point of toxicity.

Firstly, there's a lack of understanding:

Queerness is viewed as a choice, not an identity. A heteronormative environment + lack of education causes people to think that queer people are being quirky or rebelling, refusing to "listen to reason".

Secondly, Abrahamic religious and Colonial Influence:

Ancient India was kinda chill with queer people. Transexual people were ok, being able to live freely and own property, with some places even revered the trans people in their religion. Gay peeps, however, were thought to be unnatural for opposing the traditional family structure, but were punished lightly with small fines for indulging in homosexuality.

The whole stigma around Queerness started when Portugese settlors aggressivley punishing sodomy as early as the early 1500s in Goa. A few decades later, Mughals conquered their way into India and punished homosexuality with lashes/whippings/stonings. British Raj then took over almost all of India, and codified Homosexuality as a crime all over the country, and then labelled trans people as a "criminal tribe" and persecuted them.

A common point of discussion in Indian circles is the still-prevelant post-colonial starvation mindset in so many people of India - pursuing European/American beauty standards, disregard of own local culture, blind belief in western cultural concepts, racial imposter syndrome, validation from white people, sexual repression etc. This irrational distaste for queer people is a part of this mindset that has been left-behind and ingrained in the many cultures of India.

Overall, Queerness is considered dishonorable as it is seen as a form of "extreme rebellion" in the "most repulsive of ways".

Why do those commiting the violence do it?

India has always been a communal country. Even at it's peak, it was an alliance/cease-fire of hundreds of princely states and kingdoms ruled by communities. There was also the caste system that became more and more rigid and oppressive as time went on.

Anyhoo, you and your family was entirely dependant on staying by your community (community could refer to your caste, your tribe, your village, or your large family). It was a difficult task to move to a new community. Any sin or crime that you did also brought shame upon your community, and it was upto your community to correct the issue themselves and restore their honor - resulting in a heirarchical, community-priorities-first system.

While archaic, this mindset is prevelant in modern India - especially since your community is your primary support system, and there is a vast difference in socio-economic status between tight-knit and loosely-knit communities.

Those resorting to violence think that Queer people have commited a disgusting crime in a rebellious manner, all the while discarding everything that was done for them, ultimately bringing extreme shame to the family and the community. Therefore, they avenge and restore their honor by punishing the criminals for indulging in sin.

It's a toxic af dogshit mentality, especially propogated by those in power within the communities, using hate to keep their authority in line. But it is coming down slowly but steadily thankfully due to alleviation of poverty, diversification, healing from post-colonial mindset, and lesser dependance on your community for survival.