It's the anti-spam zealots, and not the spammers themselves, that "ruined email for everyone"?
Self hosting was once fun; now I hate it. Now I would only ever recommend getting a business gmail setup and using something like Mail Chimp. Not because I like either option, but fighting with blacklist operators and arrogant mail admins jaded me and now I refuse to support email servers for people.
Don't get me started on the web hosting side of this equation.
The raw mail flow may be useless without filtering, but blocking legit mail from a tainted IP addresses (tough to avoid anymore for the small business) is simply counter-productive. Our job as mail admins is to send and receive mail. We should let the receiving mail server tag the mail and let the mail clients filter.
We should never, never, never reject a message during the SMTP transaction. Just never.
There should be a new Fry meme: Shut up and accept my SMTP connection!
What you're seeing (and a conversation I've had numerous times, particularly with some individuals who seem to think it's all some Vast Conspiracy Against Personal Communications) is simply the challenges of dealing with email on a scale where you've got more peers than most people have email contacts -- where a peer is another peering email system.
It turns into a reputation management system. And it's a lot easier to deal with those reputations when you've got a handful of major public providers (Google, Microsoft, Yahoo, Aol, Inbox, etc.), and a few thousand major corporations. Once you get outside of the Fortune 500, even corporate emails get hard to deal with. At Krell Power Systems, we had a customer who required us to provide our email server IPs (already listed in both SPF and DKIM, natch) before they'd allow mail from us. The fact that they run a few machines powered by U-235 and are concerned about SCADA threats might have something to do with that level of paranoia.
But allowing all spam through, storing it, and relying on users / client software to filter it is expansive and quite error prone. The good thing about SMTP-time rejection is that it's unambiguous: any well-formed server will recognize that it's failed delivery, and in most cases the message is immediately bounced back to the sender. Accepting email and later trying to determine whether or not it's legitimate risks spoofing, Joe-Jobs, and silently-lost messages. That's actually far worse.
Much as I wish everyone could simply run their own servers, with systems as they stand now, it's just not possible.