"Saying it was "the best" means you only like that music and you are making the point that the year of any work of art you love was the high point of art. "
No. It certainly does not mean that.
What it does mean is that I have a long a varied experience of all types of music and I have the breadth of knowledge to make that statement.
I saw Tool for the third time a few weeks ago and just booked a trip to see Turandot at the Met in NYC next April. I listen to almost every type of music from almost any decade (except hip hop and rap of course).
Maybe I can explain this in a way you will understand.
Mount Everest is the tallest mountain in the world. But that doesn't mean that there aren't other tall mountains. It just means that Everest is the tallest.