Do you think they really want to help people or is it more likely they are trying to get ahead of being broken up or overtaken by a government appointed authority

I'll probably weight that warning as "might be ml interesting". Seeing that what I like (the old Web) is dying a slow death under the weight of modern privatised censorship, what they're marking as bad might become signal, of sorts.

And the first, relatively mild warnings on cigarette packages probably didn't convince many to quit, nor did posting calorie counts on fast food menus make everyone switch to salads. But hopefully it's the start of a drumbeat where this type of content becomes less and less acceptable in society.

It's not the perfect analogy of course, but I think the solution to divisive, negative, nasty online content is largely a social one not a technological one.

I'm thinking it might have the opposite effect for anyone that doesn't trust Facebook

IMO it will further antagonize them and the first reaction whoever sees this will be to go further down the rabbit hole.

I see it more as a way of nudging, herding the cattle so to speak, to get people thinking in the way that big tech wants and finds useful. This is not the same thing as discouraging extremism. By any measure, the invasion and monetisng of peoples privacy like Facebook do is extreme.