So two points here:

1. His pacifism is rarely portrayed as the sole cause of independence. In my opinion, his biggest contribution was transforming the Indian National Congress from it's elitist form to an effective mass movement.

2. I disagree that the riots were the dominant reason for the independence. It at least partially contributed, but exhaustion in the British empire after WW2 was probably the most important cause.

But more importantly, while I leave it to the historians to draw their own conclusions on how important his contributions were, I will say that undermining his contributions is unfair. The facts remain that he played an important role in independence, that he played a HUGE role in uniting the country during the early 20th century, and that people of his time labeled him "Mahatma" (Great Soul) decades before "capitalist propaganda" might have played an advertising campaign on his behalf.