It seems internal employee activism played a large role. That’s not good.
While Twitter has a right as a private company to moderate based on internal popularity, it doesn’t build confidence.
It seemed the professional moderators were saying “Trump is pushing the limits, but not crossing them” - the other employees were lobbying to get him banned.
And they won.
The message is, if you want to run for office on a controversial platform, make sure you have supporters among the rank and file at Twitter, FB, Reddit, etc, The parts about the FBI are less concerning.
Good content moderation creates a firewall between (say) the software development team and the moderation team. While Twitter had such a wall, it didn’t withstand pressure.