If I plug my iPhone into a computer, and just want to play non-manually managed music, why does that computer have to be authorized?

Question

My home base computer has been authorized to play music my friend has downloaded from iTunes.  I can upload that music to my iPhone and play it on the phone without any issue.  When I am at work, I plug my iPhone into my computer and play music through my work computer.  But the music is not manually managed, nothing is being stored on that computer, it simply streams through to the headphone jack, allowing me to use iTunes as a control panel for the phone's music library.
I can play my own music just fine (because my work computer is authorized for my account).  But I can't play my friend's music, because my work computer isn't authorized for HIS account.  Nor should I expect him to waste one of his 5 authorizations on my work computer.
But why does it need to be so?  If I'm already authorized to play his songs on my iPhone, then what difference does it make if it's streaming through my work computer or not?  Why does Apple care, and why are my music playing rights being unnecessarily infringed?  I am currently a very unhappy iTunes customer because of this.
We don't have to buy music from iTunes you know.  If I buy the CD, I can upload it without any of these play rights issues.  I can give my friend my CDs while he gives me his and all of this goes away.  The harder and more user unfriendly playing music from the iTunes Store becomes, the less likely we'll be to buy it.  This is a very simple fix.  If my home base computer is authorized and I can put music on my iPhone, I should be able to play that music off the phone anywhere at any time, so long as I'm not making a copy.  And I am not making copies.  Fix this or we shop elsewhere.

Answer 1

I spent an hour on the phone w/ apple support this morning. I went through all the trouble shooting and it appears everything is working fine...until you plug the phone in and try to use itunes. Then they put me on hold for 20 min. While they did this i had a guy at work who had an older version of itunes on his cpu plug my phone in. Voila! It popped right up in iTunes. Their product specialist told me to uninstall and reinstall iTunes 8.2. Didn't work. Then they told me to uninstall and reinstall an older version of iTunes. That way I could get music on my phone, but I would not be able to update to the newest version of the iPhone OS. That's great and all, but it really hasn't solved any problems. I'm giving apple the benefit of the doubt due to the fact they just released the newest version of itunes, a new iphone, and a new iphone OS; so there's bound to be bugs and fixes. But that goodwill probably won't last to long. So if they won't fess up to the fact there's a problem w/ the new iTunes soon and fix it I guess they're going to have to give me a new phone.