Eh. SO has its problems, and the weird "comments are supposed to ephemeral" policy is one of them, but this still seems like a weird hill to die on. If SO thinks that comments consisting of links to your own site are spam, then maybe they are spam? If they instead provided an answer (which can even be a direct quote) and put in a "For more info see X" link at the end, it'd be just fine by SO policy as well.