Content creators should be held responsible for their content. Platforms are mere distributors, in general terms, otherwise you’re blaming the messenger.

Specific to social media (and television) yes, they bank on hate, it’s known - so don’t use them or do so with that ever dwindling human quality called critical thinking. Wanting to hold them accountable for murder is just dismissing the real underlying issues, like unsupervised impressionable people watching content, easy access to guns, human nature itself, societal issues…