Here's what I think the letter is trying to say:
"Dear band I liked:
When I got into the music you played a long time ago, I was a youth with not so many responsibilities. I have had to move my attention span elsewhere while you've kept going with a career, or working some kind of 9 to 5 until the genre becomes fashionable again to perform and release new material. I let you go, and so I don't recognize what you've been doing for 10-15 years. Because of this, I say "You Suck." It's just easier that way than getting to know what you guys (and it's almost never gals) went through during the unfashionable years.
Now that you're here again, I want this perception of my youth back. It's not realistic, but it's not my fault things didn't work out. I want to be 13-21 again and 'party' as hard as I did before my body and mind changed. So don't be you now. Be you from before, because I'm too fat/stupid/drunk/ugly/poor/rich/thin/distracted/bored/damaged to be that guy/gal anymore
Signed,
A Typical audience member from long ago"