Male Bovine Defecation! If yahoo is going to provide mail services, they damn well should do it in a responsible manner. Just becaue they are big does not exempt them from this responsibility. On the contrary, the large free mail providers, yahoo, hotmail, gmail, etc. are frequently used by spammers, phishers, and other criminals for drop boxes to further their crimes.
As large as it is, AOL does a very good job of dealing with complaints and handling spam. They are also quite active in the anti-spam/anti-phishing community.
What are they doing that is not responsible other than not doing thing the way YOU think they should? As I pointed out, they accept abuse complaints, just not in the way the YOU think they should.
I would have to read the RFC, but I assume it does not specify that all abuse correspondence must be done via e-mail using the abuse address, only that they have to accept mail for that address. Which, they do. They are playing 100% by the RFC, just not in the way you want them to.