Barcelona have it proudly on display on their honours list etc. That’s good enough for me.
What’s is more than good enough and what the mackem can’t take is that FIFA, you know the people who run the sport and have the final say in everything related to the sport and what is what, recognize it as a major honor. That is the debate over before you could even begin it.
The only reason that Uefa don’t list it is because it wasn’t their competition at the time. They took it over in 1971 because it was such an important European competition and renamed it the Uefa Cup. The Fairs Cup had abolished the 1 city 1 club rule some years before we won but the FA kept it until 1974 (by which time it was the UEFA Cup) when Everton challenged this. Of course the Mackems conveniently overlook all of this, in fact they probably don’t know the last bit at all.