Facebook is a surveillance company, I guess they don't want other companies getting in on their action.
You can mark anything as spam except the ones paying Facebook for your attention.
An NSO, a Candiru or a weapons manufacturer provide tools to governments, who are at least in theory (but usually in practice) accountable to their people. Occasionally governments even act for the benefit of their people.
Facebook only acts for the benefit of Facebook, to the detriment of everyone else in society.