My stand has always been this.
Ask other Mallus here. In Kerala the number of Keralites who speak Hindi has increased due to the immigration of Hindi speaking labourers.
This has increased in Tamil Nadu as well. In terms of natural progression, a lot more people will learn Hindi on their own as per national trends. This is true in South India as well.
so in effect without declaring Hindi as national language you have increased the amount of people who understand Hindi.
People on the Hindi chauvinist side and Tamil language chauvinists are motivated by the same thing. An inflated sense of linguistic ego.
I don't have a problem with Hindi. I do however have a problem with Hindi chauvinists and those who look down on Indians who don't speak Hindi.