I mean, these companies are themselves providing the tools to mass produce what would be labelled “spam,” the topic of the OP itself.
Deleting your account may not make even a pixel of difference in their KPI graphs, but -in addition to the mental benefits- you get the moral one of not being a participant in this mess…
They only support spam when it aligns with their own incentives. They hate when other people come along and spam the platform for free.