There is a law that authorizes the government to set an MSP. That is precisely all an actual piece of legislation should do. Governments and administrative bureaucracies need flexibility to function. The details in any sane government are worked out by administrative rule making which is constrained by other laws.
This authority is used by the government and has been used by the government to set an MSP every year for 70 years with the MSP constrained by other legislation that also constrains other budgetary activity.
Or do you think instead parliament should instead figure out the MSP for 2050 now or maybe have a legislative session including a massive lobbying free for all by the buyers and sellers every year. I’d rather have the MSPs set in a rule based fashion with some limited and rarely used discretionary authority to change the rule based levels as is the case under the law now.
Under the law, all parties have to abide by the MSP, period and in any event even if they didn’t, which they have to do, the farmers can get the MSP at the mandis and directly from government buyers. Why protest? If the new buyers won’t pay up, don’t sell to them.
Have you ever in the history of the world, heard of any bona-fide business person acting in good faith, protesting a new buyer, who was previously prevented from buying their product by legislation, entering the market? The actual farmers, the vast silent majority, are, if anything happy to see this happen.