The sad reality is: there are riots in India with depressing frequency. The riots in Gujarat were not an aberration; such things happen all over the place. That doesn't answer your question; but I'm laying the groundwork.
The Congress Party (which has been ruling India for the vast majority of the time since India became independent) realized, early on, that Modi was a threat and to counter this threat, they made every attempt to tar him with the guilt of 2002. No other Chief Minister of any other state has ever been held to such standards. Bear in mind: this is the same Congress Party whose members went on a rampage in 1984, killing/burning 4000+ Sikhs in Delhi when Indira Gandhi was assassinated by her bodyguards. They even came out and said, basically, "meh, bad things happen". The large number of Sikh deaths was _directly_ a result of their deliberate inaction. I know; I was in Delhi at that time. The Army was not called out for days, just so the bloodletting could continue. For this party to turn around and accuse Modi of orchestrating the 2002 riots is a sick joke.
It is deplorable and a very tragic set of events. I wasn't there, so I had to depend on the media for my consumption of news.
The Supreme Court of India has declared Narendra Modi as legally not guilty of any crimes. From the news it certainly seems the Court has erred, although it is a constitutional body and as a citizen I need to abide by its judgement. There are of course Indian citizens who charge that the media is bought and paid for, just like other countries.
If you're asking why I voted for the BJP, in my city the local BJP leader is very good and the other party leaders are very corrupt.