I agree with your original post. I’m not a fan of dual accounts as I think they are in many ways unfair. I have played a couple of rounds as a dual though.
When I first started playing dual accounts weren’t really heard of and you could have fun talking with your enemies to play mental games and find out their online times!
That being said, they are allowed simply because it’s impossible to block them. How do TG know who is behind what computer? It’s the same reason the rules recently changed to allow tech accounts.
I can also sympathise with some people... many people just don’t have the money or the time to try and compete at the higher level of the game. Being a dual (or one of many) can help keep that travail addiction alive lol.
I’m afraid its a situation which will always be ‘If you cant beat them, join them’