Communists simply want to put India on the same path as in olden days (scared of globalisation, security treaties)...Remember Left parties did the same when Narshima Rao initiated economic liberalisation....
I think for us, US is better than China...For Communists its the other way...China is spreading its naval muscle all around us...they have installed bases/radars in Myanmar, bhutaan, assisting pakistan in all aspects, even provding weapons to Srilanka...Infact chinese are smart that they dont fear any country for signing any deal...They negotiate any deal to their advantage....They do business with US, buy weapons from Russia, Suppress rivals like India by using proxies(communists)...