Mastodon isn't in charge of moderation though, that's up to the individual instances.

Also, Mastodon is tiny, and spam is a numbers game.

But are you not somewhat agreeing with the point that you're implicitly arguing against: "[This isn't a problem] if I [am] only seeing updates from the people I actually know and explicitly connected to on the social graph. The current problem exists because the content is chosen algorithmically."

The size of a total network is irrelevant until you start randomly connecting nodes.

At the moment "no one" is on mastodon. The folk there are the few, and are likely a self-selecting group that are resistant to spam or scams. Therefore you don't see (much) spam or scams there.

Of course should it become popular (side note; it wont) such that my mom and her friends are on it, then the spammers and scammers will come too. And since my mom is in my social graph a lot of that will become visible to me.

Enjoy mastodon now. The quality is high because the group is small and the barrier to entry us high. Hope it never catches on, because all "forums" become crap when the eternal September arrives.

Mastodon is perfect for affirmation of your worldview and strengthen your social bubble because instance rules are intolerant to random kind of opinions.

There is always NOSTR. Over there you follow however you wish without such artificial walled gardens.

Tip: If someone is trolling you, they can also write to your texts without a chance of you stopping them. No perfect solution exists, I guess.

You are correct that since nostr is censorship resistant, you can't really prevent someone from posting something, but you can prevent being exposed to it on your side. If it's a single nostr account (npub) sending you something you don't want, then you can block or mute them (the blocking is done in your app on your device). If they try attacking you at scale, then you can rely on web of trust (i.e. only allow content from people you actually follow, and 2nd degree) - this is now often the default.

Because everyone knows, Twitter and Facebook have never arbitrarily enforced moderation on political topics they consider distasteful.

Yet. There are lots of sign spam is coming to Mastodon and there is real concern by a fair number of people who are there. Anyone with a lot of followers will be tagged often by spam (if you tag someone all their followers will see your post)

The simplest explanation for this would be that spammers are not targeting Mastodon.

As someone who uses Mastodon I can assure you that spammers do target mastodon. So far it is only a few though and so human moderators are able to keep up. I doubt that will last long.