Without knowing much of how Indian law is spelled out, this would be very clearly permitted language in every other liberal democracy. The narrow exceptions for "fighting words" need to be very explicit physical threats. Insults, even lies, are well within the realm of protected speech. Protection against causing offense is exactly what free speech rules are written for. Americans say absolutely awful things about our presidents whether or not they're true and none have ever been punished for expressing an opinion no matter how odious.
Modi and the BJP may not literally worship an assassin, but they absolutely do support violent confrontation against Muslims. The kind of thing that is not only offensive and "fighting words" but a very real existential threat against a minority of Indian citizens. Yet they don't receive punishment because they have the protection of the government. It makes it seem very obvious that this prosecution is just government oppression.
https://www.nytimes.com/2022/02/08/world/asia/india-hate-spe...