Why is Google so often linked to spammers and scammers?
My own take is that it's just because Google is too busy becoming EVIL to worry about the small fry competitors. If not Google would give a much higher priority to fighting the criminals. For example, imagine that Gmail included USEFUL and POWERFUL tools to iteratively analyze the spam and to go after ALL of the spammers' accomplices.
I disagree that the problem is "liberal-lefty" anything. In general, it's much harder to bribe people who are acting out of ideology, and we really should consider freedom of speech questions.
Having said that, and imagining that Google decided to oppose evil, that Yahoo magically became competent, or that Microsoft became sincere, let me offer a couple of thoughts on spam:
1. If email is NOT desired by the vast majority of the recipients, then it is spam.
2. The large email providers could track this simple metric. Legitimate email advertisers provide subscribe and unsubscribe options, and the large email providers can TEST them with honeypot addresses.
3. Spammers should be leaned on ALL the way up and down their chain of accomplices. ANYONE who provides any support in ANY form to a spammer should get leaned on.
4. You can't expect any spammer to become a decent human being. Only a total sociopath would participate in such a business. However, you can make it much less profitable and that will persuade them to crawl under less visible rocks. Google could do MUCH more along these lines--if they hadn't become so evil, that is.