Personally I think the report system was based around expedience, or rather, “keep it cheap.” They needed something to stop the worst offenders, but it’s very clear those at the top don’t care to spend too much money on their players (customers), so cheap was the easy decision.
Having said that, back when they had millions of users, it’s too much to expect every report be manually reviewed by a human. Most large platforms of all kinds have an automated system. I’m not defending it, but cost factors and practicality will more often be the most weighty factor for determining these kind of systems for Billion dollar companies.