@ Keith Doyle
"blocking systems that misrecognize even ONE legit email as spam should not be tolerated, unless it's one that you yourself installed on your own email accounts."
Vote with your feet, Keith. You aren't paying the bills for the bandwidth stolen by the spammers (and neither are the spammers). Your ISP is (usually) doing their best to avoid "false positives" while also avoiding "false negatives." And I venture to say you aren't running your own server, either, so you have *NEVER* installed a blocking system, and probably have no idea how they work.
Blacklisting certainly works - my users, for example, expect no email from China, Japan, Thailand, Korea, UAE, Turkey, Israel, or numerous other nations which are hotbeds of malicious software, and the proximate sources of most of the spam aimed at us. Such nations are "block on sight" and our mail server becomes "invisible" to them.
Greylisting is something you clearly don't understand, but suffice it to say that it's less likely to generate "false positives," and more likely to generate "false negatives" than blacklisting does, which is why it should be used *in conjunction with* rather than instead of blacklisting.
e360's own ISP is not the issue; clearly you don't grasp that concept, either. It's the users of other ISPs who have cried out to their admins to "please stop the spam," and those admins have done their best to oblige.
Spamhaus has a policy of listing IPs (and ISPs) *only* when there is a well-documented history of spam originating from them; Spamhaus also has the best track record of *any* IP list provider in avoiding "false positives" (e.g., if the mail is coming from a known spam-source IP, and it's rejected by my server because Spamhaus has listed that IP, it's not a false positive).
I can recall two incidents over the past decade in which Spamhaus suffered a typo which caused a false positive incident. Both cases were cleared up within hours.
My best advice to you, if you are unhappy with your ISP, is to change ISPs. For example, I will undertake to provide you with totally-unfiltered email, for only US$2000/month (that's my best estimate of the cost of operating the server, cost of bandwidth, and cost of storage).
Or you could try to get a grasp on what the *real* problem is and quit whining about things of which you clearly have less than zero understanding.
I have no affiliation with Spamhaus, other than having previously been a satisfied user of their lists, and once or twice being named as a co-defendant with them in a lawsuit by spammers trying the "improper joinder" approach (in other words, "let's sue a bunch of mostly-unrelated people and see if any of them will pay us to leave them alone").