Social network moderators are almost always low-paid, low-power, low-profile employees. It's not a great job. It's a high-volume job, like an assembly line. The highly compensated Twitter and Facebook software engineers are not doing the content moderation. They don't have the time, and they would run away screaming if they had to do it for an hour. It's likely that a lot of this work is even outsourced.
I assume they have created an hierarchy with a number of different roles. That's generally how you scale people-intensive tasks. I have no idea why you would want to classify all of those roles as "assembly line".
Let me ask this: what evidence is there that the results of Twitter's censorship are actually in line with the political beliefs of Twitter's employees?
In many cases, Twitter's rules have been used to suspend accounts that people thought they were supposed to protect. And Twitter has gone out of its way and contorted every rule in order to protect the President from censorship and suspension, out of "public interest", despite the fact that he has repeatedly violated the rules that would have caused anyone else to be suspended.
That fact alone makes me believe this is a result of internal pressure.