Communism

No problem!

Regarding "unbiased sources," you'll find that there's really no such thing in general. Bias is like perspective, everyone has it. Here's a ProleWiki page section going over state media directly speaking about the "June 4th Incident" as it's called in China. ProleWiki is a Marxist-Leninist Wikipedia, so definitely biased, but also has sources backing it up for most claims.

As for "Maoists," Mao himself was a Marxist-Leninist. His contributions to Marxism-Leninism are called "Marxism-Leninism-Mao Zedong Thought." Maoists are a subsection of Marxists after Mao that believe certain individual characteristics of the Chinese Revolution are universal, rather than individual, ie they see Maoism as a higher stage of Marxism surpassing Marxism-Leninism. They get called "tankies" just as much, even if they reject most Socialist states as "valid." "Stalinism" isn't really a thing either, Stalin took the writings of Marx and Lenin and synthesized it into Marxism-Leninism, but didn't really create any new theory. Those calling people "Stalinists" are generally trying to fearmonger around the name of Stalin, even if Marx, Engels, and Lenin are the broad majority of Marxism-Leninism, and Stalin more the first person after Lenin to really collect how Marxism and Leninism had changed and developed over time.