When Karl Marx and Engels came up with their theoretical-political framework, they had researched the history of class struggles and proposed a theory.
I think communism was interpreted to eventually evolve into Socialism, which is what is practiced in China today. I think the Left should be banned. The ideology itself does not hold water in the 21st century. West Bengal used to have excess of Power and now it buys power from other states.
A little bit of cleansing is also required, where we have different parties coming to power. We need some freshness in the approach. The Left in West Bengal have been there for so long, it is like wearing the same undergarments and socks for months at a stretch.