Spam is the use of electronic messaging systems (including most broadcast media, digital delivery systems) to send unsolicited bulk messages indiscriminately.
Email spam, also known as unsolicited bulk Email (UBE), junk mail, or unsolicited commercial email (UCE), is the practice of sending unwanted email messages, frequently with commercial content, in large quantities to an indiscriminate set of recipients. (thank you wikipedia)
Now, if you do what you're suggesting, not only are you violating ToS and Privacy Statements, you're setting yourself up for fines and/or jail time.
That's the harsh view of it. The reality is that more than likely your host or ISP will slap you down first, which is terribly inconvenient. It takes quite a bit for the gov't to get involved....like total gross negligent spamming of any and everything in sight.
That's why you see "By clicking here you agree that you may receive emails from our affiliates/partners/networks/etc." This catchall statement covers and (somewhat) protects you. Let's be honest, how many people really alert the authorities (or anyone for that matter) that they got an email for a bigger dick? People that don't use the internet that often get annoyed - but it won't go nowhere. People who do use the internet often don't remember shit from shinolah as far as what they clicked and what they agreed too, so they are likely to ignore/delete the unwanted messages. I for one get hundreds of spam email/day on one of my email accounts. I scan them over long enough to make sure I didn't miss anything important, then delete them. Its like getting direct marketing mats in your mailbox. You didn't ask for it, but somewhere along (a very long line) you agreed to receive stuff. Are you going to contact you local post office, legislator or city official to complain? Probably not. Even if you DID, they'll probably smile and nod.
Bottom line, scraping isn't as big an issue as what and how you use what you get.