I think the point is that "pissing off" radicals is more cathartic than useful. What moderate people want is to thwart their ambitions, but ideally de-radicalize them so that they are no longer dangerous people in need of thwarting. The main argument I see against a move like this is that it may temporarily achieve the former but only at the expense of the latter.
Personally, I believe that de-platforming is a useful tool when radicalization is spreading like a contagion, but only if it is applied in a consistent way and with well defined boundaries.
Personally, I believe that de-platforming is a useful tool when radicalization is spreading like a contagion, but only if it is applied in a consistent way and with well defined boundaries.