Ooooh now I'm confused, but as a noob to this forum here's my opinion
"It's all down to perspective!"
Palm are wrong, these are hostile business moves
Apple are right to block, this is a threat to their business model
From the point of business ethics, they are trying to sell their product off the back of a service that apple believe is their monopoly.
No doubt apples business plan shows a break even point where they had to sell number of IPods/IPhones before they would have cleared any money payed out to the Music Industry in terms of licensing. So the business model would have included "ITunes Store" "ITunes Software" and "IPod Hardware" as parts of a symbiotic system.
Having some jerk selling other hardware, therefore would affect apples ability to offer music at the price that it does!
Palm are right, everyone should be invited to the party.
Apple are wrong, how dare they discriminate and monopolise!
From a customer point of view, I might love ITunes Selection of music, and understand that to access it I MUST use their ITunes software, but there are plenty of legitimate reasons for picking something other than an IPhone,
Hey, if Walmart bought Ford, and wanted to sell more cars, would they be morally right for turning away anyone trying to drive a Toyota into their parking lot? That's discrimination!
I mean the argument that they cannot guarantee the user experience with non-Idevices is just wrong.... Its a straight forward usb file transfer, OSX can transfer files to USB sticks, its not that complicated.
Conclusion
I suppose it comes down to this....
If apple were to say that they're only allowing apple devices into the store because it's their business model is finely balanced around having to sell Ipods to give low music costs to the consumer

, or guarantee licensing conditions to the music suits

Then thats fair enough, since by not preserving the lock-in the whole system would fail.
They have the consumer in mind.
If however apple were to say that the "ITunes Store" part of the business and "IPod Hardware" business were both self sufficient, then by definition the aren't reliant on each other for survival it would be more like they were trying to dominate. That means they are running a monopoly where they hold their own profits far above the consumers happiness.
(Thats where the European authorities will cry "Monopoly", and apple would get the microsoft treatment!)
One mans "Symbiotic" and "Synergistic" is another mans "Monopolistic", "Cartel". They are both right, they are both wrong.
- If apple would be badly hurt by Pre getting in, then I side with apple.
- If apple just made a bit 0.5% less profit of their huge Ipod sales, then I'm a'gin them.
Just for reference,
I don't own any apple gear, but have bought the 16Gb Nano, and the 32Gb Iphone 3Gs as presents for my non-tech girlfriend. She loves them!
I'm using a 5 year old laptop with Ubuntu, Want a change, hear good things about Windows 7, but really like the 13" MacBook. (And colleagues are giving me a hard time for even considering 'overpriced' apple.)