The point in
limiting yourself to the minutes or even hours of a song is to limit the time you spend listening to music while maximizing your pleasure.
I'll try to explain my viewpoint in other terms so that you might understand it better:
I view songs as being like assorted chocolates in a box. I remember that when I was a child, I used trial and error to learn which chocolates I liked. This led to a lot of discarded, half-eaten chocolates. Later, I made my selection after reading about the characteristics of the chocolates. I found I tended not to like cherry liquor fillings. (Similarly, when I read that a song is 15 minutes long, I tend not to want to listen to it.)
I don't feel I have to eat the whole box of chocolates or even a whole chocolate candy out of some sense of obligation to the chocolate-maker. If I do try a piece of chocolate that has cherry liquor (a long song), and I find that I don't like the first taste (the first 5 minutes), then I don't force myself to eat the whole thing. And even if I like the chocolate at first, I usually find that I start to get sick of it if the chocolate bar is too big (just like I can start to get tired of a long song).
My point, contrary to yours, is that
we can respect a band's choice to make a song short or long, but that doesn't mean we have to listen to the whole song or even listen to the song at all.
My tendency to avoid or dislike longs songs has nothing to do with respect or lack thereof for the musicians. A song isn't the ruler of a single-party dictatorship where we are forced to give only adoration. Music is a democracy where we can express appreciation and criticism, and elect a different song when we want.
In fact, the musicians I know
like constructive criticism (when solicited). Giving them my honest opinion, such as by telling them if I feel a song is too long, actually shows my respect for them.
More about this issue of respect: do you feel you have to listen to all of
Robert Rich's two-and-a-half-hour song "Somnium" to show your respect for him? And, if so, given that he intended the song for people to listen to while dreaming/sleeping
or while awake, do you feel have to listen to it with your full attention to show respect?
If you choose not to listen to this song in its entirety, I won't feel your choice means you lack disrespect for Robert Rich's creative process. Perhaps your choice simply means that you have other ways you want to spend your time:
Robert Rich -- Somnium (Part 1 of 4)
This song lasts over two hours. Are you going to listen to it all?
Robert Rich - Somnium Part I - 1 Of 4 (Somnium) - YouTube