We Marxists have a saying: no investigation, no right to speak. Given the immense hostility to Marxism and to socialist countries in the English speaking world and internet, those of us that come to Marxism generally only do so through reading, studying, organizing, and facing material reality head-on and finding that the dominant narrative doesn’t line up.

I used to share skepticism for China like you do now, and it took a lot of reading and conversation with comrades for me to come around to being pro-China. The kicker there is that you’ll find those supportive of socialism, Marxism, etc have mountains of sources ready to go, because most of us have been through that same process, while most of those opposed to socialism and opposed to China have done so through cultural osmosis.

In general, as long as you maintain an open mind and try to speak on what you’ve investigated previously, you’ll rarely be outright wrong.

For what it’s worth, me being more civil is more of a personal choice than the norm, I’ve been doing this for years and have found good success by doing so. Others will also have their own collection of sources, but may not be so civil.