Because the past actions have left us with no faith in its abilities to act responsibly. In November 2016 the government just woke up one night and declared the highest denominations of Indian currency as illegal tender (not just not legal, but possession of it beyond a set date would be treated with jail time). This was apparently to curb black money. Everyone knew that black money was almost never stored in cash, but in land and real estate. Tonnes of evidence then came up how BJP candidates themselves distributed boxes full of newly monetized notes to the ones they favor. This was during a time when the common man stood in queues at cash points to withdraw their own money only to be rationed a fraction of it due to distribution problems with the newly minted notes.
The effects of this gimmick was the obliteration of the small sector economy throughout the country and is now the backbone of financial crunch the country is facing. Also it completely failed to nail the black money problem it was proposed to solve. Widespread corruption and the BJP candidates themselves made sure that their rich friends cleaned up the money (I got all kinds of acquaintances who did).
We do not live just in the present. My optimism with the current government has eroded by their actions in the past. When such laws alienate an entire community of people by their religion (or skin color or economic status) and we are talking about holding them in detention camps, do we keep calm and let the atrocities begin to unfold or do we protest?
Let me get your argument straight here: You are saying that because the British tried it and it didn't work that makes it ok to try again? Are you hoping for failure or success here?
Anyway, to address your question:
Because then the British were a small minority, exhausted by WW2 attempting to oppress a large majority who clearly had natural justice on their side.
This time it is a large majority attempting to victimise a smaller minority for a reason which historically has led to wars, genocides and mass killing.
But would it bad to if only the good happens? What's wrong with a bit of optimism?