You do not understand your own metaphors. Let's limit ourselves to two examples. The worst, email, and the best, megaphones. Best still means bad.
Email: It's not a public platform. I can spam, but only if I have your email address, and you can block me, and the email spec doesn't provide me any resources which amplify my message. If I want to send out lots of emails, I need to provide my own resources. Facebook provides resources and a method to push a message to many people, most of which are not specifically targeted by it.
Megaphones: These let me shout a message out. That's distribution, so it's a better metaphor than email. However, a megaphone is only useful if I can shout through it where people will hear. If I use a megaphone in a deserted forest, nobody will pay attention. I have to use a public place, a venue, in order for my message to get out. So, the people who run that venue have the choice to let me do that or to make me stop. Facebook is such a venue, and they provide tools that have similar power to a megaphone there. They have the ability to stop someone there and the ability to let them continue.
Opinions differ about whether Facebook should be responsible for this kind of thing. That might be fun to debate. I'm not doing that yet. Instead, I'm focusing on these hideously inaccurate comparisons. That's not how Facebook works, so if you intend on arguing your point by comparing two things that are not similar, we couldn't actually debate the point in question.