It's not about media sync
Rather, it's about the fact that iTunes is the defacto media APPLICATION for a majority of users.
Microsoft's Media Player USED to be the defacto standard for playing media - until the iPod and iTunes showed up. Since iTunes got the world to thinking that 99 cent songs was the "right price", rather than the paltry catalogs of the media companies or the unlimited but shady P2P download sites, it became the place for people to buy music and manage their collections.
And THAT is the issue Palm has with iTunes. Media sync alone would be a justified lock-out, but with Apple controlling the media PLAYER as well as the storage of user media, this becomes a restraint of trade issue.
Yes, there are other players that "fool" iTunes into letting them work with the service, albeit in a less than integrated manner. Palm, however, has taken Apple to task on what it REALLY is doing: forcing consumers to use its products.
I personally have no problem with Apple doing this: after all, they made the investment and suffered all the jokes and jeers when iTunes was launched. If this is for Apple devices only, so be it. Remember, Apple only reluctantly created a version of iTunes for Windows. And has NEVER created one for Linux.
If Microsoft had tried to make Media Player only work with Zune, regardless of Zune's success, it would have been up in front of the DOJ in hours for restraint of trade. If Apple is doing the same thing, and has a significant enough market share to sway a consumer by ransoming a consumer's purchases to only Apple products, then let Palm fight it out with them.
Maybe Palm is the Opera of the US - maybe we'll see Apple give you a choice of music player as part of a consent decree.
Or maybe not...