I am still unsure WHY CPA + classifieds is not allowed?

I am aware that there is a LOT of scams going on on classified sites like CL and there have been lots of scam schemes in the past with tricking people into all kinds of offers with VERY shady techniques.

But i dont understand why using CL and similar sites in a SMART and intelligent way is still not allowed - given there are ways to do it eg. by collecting emails and directing people to offers in *NON SHADY* ways, without tricking them.

I have read that networks reject CL etc. traffic because of bad traffic quality..which i can't understand either because there would be means to make email lists of highly targeted prospects.

Ok, let me just pull something out of my head....looking for people who are in need of money...and then direct them (after the email is collected) to one of those payday small loans offers and tell them this is a good way to get a loan quickly.

Wouldn't the traffic quality be high since it is already filtered by emails and all the people would be very interested in getting a loan?