have to agree here. deplatforming is definitely not the answer. To use a crude but fundamental analogy, if you want to reduce the concentration of something you need to dilute it not separate it from the rest
As for your dilution analogy, deplatforming does have that effect because it breaks up the filter bubbles of the hate groups. It makes the media feedback loop of hate more difficult for those caught in that. From the perspective of those considering the hate, their input has been diluted.