If a person wants to learn Hindi , he can easily do so
But putting 3 languages in an official school curriculum is burdening the children
Languages should be learnt out of interest not compulsion
My neighbour's daughter was curious about Chinese ,So she started learning it slowly just out of curiousity over 3 years
Now it is helping her in her career.
The same goes for any language. The 3 language formula was proposed after a lot of thought & consideration. It aimed at preserving ones local languages & promote the concept of a bridge language to ensure a common mode of communication across the length & breadth of a multi lingual nation. Hence English & Hindi in the latter role with no single national language but a number of official languages.
I think all of us have been thru 3 languages I school. It didn't kill us. Not sure why should the younger generation consider themselves especially burdened.
Languages learnt out of interest is another topic altogether. The Hindi belt just like TN which have essentially followed the 2 languages formula ought to put this to good use and opt for a 3rd local or international language. I believe that's the idea behind sticking to the 3 language formula.
My sympathies with your neighbor's daughter. She's certainly chosen an excellent time to learn Mandarin.