Blizzard’s implementation of RDF left something to be desired however, by itself, you are correct - RDF was not a core problem. Its actually blameless. So youre right in one sense but just wrong in the other.
Its how the tool was used. So the problem is the players. When you get something for nothing there’s always a cost paid somewhere and players regarded others more as a means to an end rather than another human being enjoying the game with them.
In classic WoW player style, we just cant have nice things because we cant help but use them to our own detriment. I dont know about you but I dont give a four year olds a book of matches each and tell them to go play in the firework factory.