My question is why doesn't google realize that it is quite possibly a hack?
They're actually working on that - but it's a question of scale - seriously humongous scale that produces many many edge cases and complexities. And always remember, Google's first imperative is to give their search user a good experience, and not to treat every website in the index with TLC.
When even the owner of a site doesn't know they've been hacked, and they're using the site all the time, then think of how hard it would be to automate that detection at the scale of the entire web... and as a free service, no less.
Do you mean links within our wordpress site or showing up as backlinks pointing to our website?
The parasite links are on your Wordpress site, and the scammer-spammer then launches promotional backlinks that point to your pages. In fact, your site can be pointing to another site from further down in a promotional link pyramid scheme and you might have lots of trouble even seeing the final URLs that the scheme is trying to promote.
I am told that the dead giveaway is that you can see cloaked links in the RSS feed
That can be a sometimes giveaway - but only if your feed contains the full article. Even then, these guys are too clever for "our own good", and they may well be scripting the hack to avoid that pitfall.
To catch the hack this way this way, you wouldn't be looking at the feed at the time of publication - you'd need to be checking the historical entires in the feed a while after the initial ping.
Some of these hacks have experimented with dropping cookies so you can't see the parasite links after your first time - so if you are investigating, definitely turn off cookies first. Some also use the IP address of the visitor to block a repeat viewing. There can be a very nasty technical tangle to unravel in some cases.
If this direction (a hacked site) appears fruitful to you, I'd still spend the energy to follow-up on those who are duplicating your content. They might even have scraped your parasite links and when you find the duplicate, you'll see more evidence.