Let's be pretty blunt here; it's very well documented that people tend to idolise the period when they were in their own prime and bemoan the state of music since then, while discounting music before then. Yes, you have some people who will not fall into that, and no it doesn't make your opinion any less worthy if it happens to coincide with that, but let's bear it in mind.
I became a U2 fan in the 80s, but think the early 90s was their best period, although I guess you could say I was in my 'prime' (subjective term) then, too. I also, on balance, prefer music from before my 'prime', so I far from 'discount' it- for example, I became a Rolling Stones fan in 1989 when Steel Wheels
was in the charts and yet I don't have much fondness for it now, but consider the late 60s to early 70s to be their 'golden age', which was before my time.
It's why almost everyone thinks that the era when they became a big U2 fan was the TRUE golden age of U2.
You're wrong there. According to my old poll, the clear majority of fans introduced to U2 in the 00s consider the 90s to be their favourite era, nearly half of the new fans in the '80s consider the 90s to be their favourite era, but you are right about one group- the clear majority of the 90's intake think the 90s is the true golden age of U2.