I think he was referring to double spending. You should check it out, you would learn a couple of things about bitcoin.
I'm not sure if you're trolling or not but almost all of what you said are false. Anonymity? Really? Did blockchain ask for your ID when you signed up? It didn't, right?
Not almost, everything he said is not true. He can choose do he wish fast or slow transaction, according to that he will pay fee. Reversing bitcoin payment is not possible, and this is the first time I hear that transactions can be reversed, where he heard about that I don`t know. About anonymity, for now we are anonymous as we can be, but it`s question for how long we can stay that way. Some companies and shops insist on ID verification, that will happen with btc one day.
Well there will be always be some alt coin that will ave some speciality more developed then bitcoin have, but bitcoin is unique cause bitcoin synthesize all qualities on one place.