Depends what you consider the radicalization pipeline to be. For example, if you ban a user from Twitter, and they end up on Parler, they're gonna be exposed to a lot more "radical" (for lack of a better word) stuff than when they were just on Twitter. It's really not guaranteed that banning "undesirable" content actually does disrupt the pipeline, so much as just further balkanize and radicalize the dissidents.
I like to do in-depth research for myself (example: watching an entire Trump or Biden speech instead of relying on a selected soundbite), viewing the original video or source instead of blindly believing on what mainstream media says about them.
Unfortunately as more things get censored from social media/YouTube whether fairly or unfairly, it looks like I'll have to spend more time on "alternative" platforms, being exposed to the stuff that is common on such platforms. In the end, there's going to be the Twitter echo chamber, and the Gab echo chamber, etc (note that Parler seems to be dead).
But your past the initial pipeline for radicalization.
A slightly more effective approach for you might have been to remove such videos from their recommendation algorithm. But, that doesn’t mean it’s ineffective for people who would be initially discovering this stuff.
> Depends what you consider the radicalization pipeline to be.
Platforms, by their nature, are mostly worried about what's happening on their platforms - when it's occurring elsewhere, it is no longer their problem. It is a mistake to think YouTube wants to bring an end to all misinformation everywhere - their focus starts and ends with misinformation on YouTube. Balkanization is the best option they can hope for, as long as it's not on YT.
But that banned user cannot radicalize others on twitter, the larger platform with a wider reach.
Parler is a niche platform for people already down the rabbit hole.
For the Romans, all that mattered is that the followers didn't wish to start an actual rebellion against Rome. Which doesn't seem like they did from the writings of Paul and the rest of the NT and early Christianity.