The text you're quoting has to do with how we distribute volume, NOT how we enable spammers. High volume campaigns does not equate to spamming. You can send a 10-email campaign that IS spam and a 10,000-email campaign that is NOT spam.
Supporting a system where people can mass-send emails = enabling spam.
How absurd will you extend this argument? "Oh, yeah, 99% of my customers are spammers, but I'm not the one making them click send! They could've just paid, twiddled their thumbs and not do anything with my product!"
Maybe that's a convenient reason not to check.
In what instances is high volume not spam when using this service? Given one legitimate use case where a customer isn't better off using a cheap MailChimp account.
We never had to bother avoiding any of the measures you deliberately subvert, because our mail was all legitimate.
Granted, doing a 'mail run' with that volume took about a week, but whatever.
If your (client's) recipients aren't all double-opt in, then what you're running could very easily be seen as irresponsible (and that's me being polite), no matter how much money it's making.