Doesn't the Maoists consider all those parties to be pro-imperialist or revisionist?
BTW, do you happen to know if the Maoists have any significant foreign support?
"Doesn't the Maoists consider all those parties to be pro-imperialist or revisionist?"
Of course. The Maoists' first victims were the workers of those political parties -- not the royal army. But, after the royal takeover, the politcal parties lost their remaining control of any foreign $$$ coming in. They basically lost their income. Now they are as desperate as the Maoists. Thus, the alliance.
"BTW, do you happen to know if the Maoists have any significant foreign support?"
Indian communists and the communist groups in Europe are their main supporters in terms of money and supplies. They loot banks to finance pretty much everything else. They also abduct children and engage in extortion, kidnap teens and indoctrinate them, and of course recruit among the poorest peasants and lowest classes who have had enough of the reactionary feudal system.