So does browsers fall into the same section, because they display ads on the pages that might link you to unwanted sites and finally malware?
Browsers don't display ads; web sites do. Televisions don't display ads; the broadcaster does.
A browser's function is to display web content chosen by the user; OpenCandy's, et. al. function is to display advertisements, hijack your browser, etc., not chosen by the user.
OpenCandy is an advertising software module, and not a PUP (although some might have various opinions depending on how they perceive it).
I say again,
Potentially Unwanted Program. Nobody says, "Hey, I really wish I had OpenCandy; where can I download it?" or "I really can't get enough advertisements, how can I get more?" No, it is bundled sublimely with completely unrelated software.
Potentially pretty much makes it absolute.
If an anti-
PUP program is trying to convince me that it will stop all software I
potentially could not want, then it better do so or it isn't very good at fulfilling its claims. OpenCandy is well-known; to miss that would be like a sieve letting boulders go through. Or, their interests and mine don't coincide.