What I take offense at is this idea that making money is bad. It's not.
I'm providing something that some people find useful, and since in this particular instance, there happens to be a way to make a tiny bit off it to reinvest in more books, I'm not ashamed to do so.
Making money is obviously - very, very obviously - not my primary use of this site.
You know another thing people do here? We promote our own stuff that we worked hard to build. Other communities intensely dislike that, but we don't, as long as it's kept within reason.
I think you're taking this as much more ideological than it is. When someone honks their car's horn at you, it's not because they have taken time to construct a reasoned analysis of the legal status of your behaviour -- it's usually because you did something which they did not expect. In some sense this is 'always right' with cars: a lot of traffic safety rides on our ability to safely expect what others will do, so if your actions are unexpected they are often unsafe.
When TezzellEnt posted a new version of the link, he/she did so because that little referral token is a sort of egg on your shirt in precisely the same way; it's unexpected. It's not necessarily an "idea that making money is bad." Nobody has said anything like that (except you, to refute it, of course). Heck, part of why it's unclean has to do with domain separation: if the egg is on your fork, it is 'clean', but if it falls on your shirt then it magically becomes 'dirt'. The egg of course is chemically identical, but one of them appears in a domain where you don't expect it -- an otherwise blank shirt. Similarly rmrfrmrf's first complaint ("issues arise when the content you produce for this site is influenced by your desire to make money") is not a referendum on your contributions as a whole but a statement that "you're crossing two domains here, and if those domains cross too much then this site will not be a place which we enjoy frequenting."
Because I haven't actually engaged the ideological side yet I might as well do that too. You're not just "getting money from Amazon" but also being co-opted into "advertising for Amazon" -- and, as you say, you were bought in this way for only a few cents. What you think of as a strength -- that you only make a tiny amount off of it -- is in some sense actually a weakness. acjohnson55 put this above as being "thought of as a shill."
> I think you're taking this as much more ideological than it is.
I think for a lot of people, it's a fairly reflexive dislike of referral links, rather than something they think through deeply. But at heart lies this idea that "OMG, he made some money off it! Impure! Impure!", when it's pretty easy to judge, on a case by case basis, whether a person is contributing or spamming that on a site like this.
Also: any links I put probably would have been to Amazon anyway, out of convenience, although sometimes when Wikipedia has a good summary, I just link to that. So my behavior does not really change other than attaching the referral code.
I'm providing something that some people find useful, and since in this particular instance, there happens to be a way to make a tiny bit off it to reinvest in more books, I'm not ashamed to do so.
Making money is obviously - very, very obviously - not my primary use of this site.
You know another thing people do here? We promote our own stuff that we worked hard to build. Other communities intensely dislike that, but we don't, as long as it's kept within reason.