There seem to be some misconceptions here about Indian 'communist parties'. Just because they are called communist parties, it does not mean that they're actually 'communists' like 1960s China or USSR. They have to follow the Indian constitution, stand for elections like everyone else, and so on. And being elected at the state level, as opposed to being elected to the central government, they cannot make any changes to critical things like Indian foreign policy, Indian defence, and so on.
Therefore, these are 'communist parties' only in name. They try to come up with a weird mishmash of communist and capitalist ideology, and end up failing thoroughly.
And may I add, their days are numbered. West Bengal will elect Mamata Bannerjee next time, and Kerala will move on in the elections after the next. Same with Tripura.