I'm not whining, it's just in bad taste. I actually up voted your post because it was useful, and I DID buy that book this morning (just not through your affiliate link).
This isn't the place to be using undisclosed affiliate links. Had you disclosed it, I would have happily bought it through your link as it would be a legitimate referral.
The fact that there's an affiliate link has no bearing on that.
If someone's spamming the site with affiliate links, they ought to be banned. If someone posts a link with one from time to time, I see absolutely no harm in it. I think it's pretty clear what's what.