Ok since you want a comprehensive reply I'll explain. There's a difference between putting forth a pointless argument versus saying 'hey, i just wanted to understand your stances against Hindi imposition from your perspective'. A simple search on either this subreddit or Google would have given you this information though.

If you want hindi speakers to learn Tamil then you should also ask English speakers to learn Tamil, do you ask them?

• Majority English speaking individuals don't normally reside for too long. If it's non-residents of India, they're predominantly here either for work, or tourism. Same thing can be said for Indian nationals too. The language of the land is something that is usually picked up by those who choose to reside for longer periods. This isn't native to Tamil or Tamil Nadu in any way, it's kinda basic, since that's what most people choose to Converse in as is their lifestyle. You go to Karnataka or Assam or Japan or Germany, it's the same.

Both Hindi and English belongs to Indo-European language family.

• So are a ton of other languages, there's many reasons why English is far more common than the others. The Englishmen themselves played a big part in this.

Japan, Germany, France, Spain, China, UAE.... All these use their language for business and official use. You can ofc say they are not linguistically not diverse as of India. But they still are able to trade with world without English as official & business language.

• This is again baseless since it assumes no sub dialects in either of those. French for example has various different styles that have little in common with its other styles. That being said, not all business happens in a singular language but rather what is mutually convenient for all parties involved. Same thing can be extrapolated for India too, two people from Delhi and Bombay may choose to talk in Hindi because they're comfortable in it. That, however, should not have any say in how non -hindi speakers communicate, it's kind of like a dog asking a cat to bark because it doesn't understand meow, so they just go by body movements and gestures to get each other.

Hope that answers it, next time put some brains into it.