Sorry Tom, I don't see it.
These musicians aren't scabs -- they're not writing for these shows. You can deride actors for crossing the picket line, because they're part of the same community as the writers and should show support for them.
Musicians are in the same boat as the wardrobe people. They could make an ethical choice to support the writers, and not work on these shows, but its not necessarily fair to have that expectation of them, especially given how it could affect their livelihoods. A lot of times appearing on one of these talk shows can be a big break for a band, and I think you undersell the importance it can have on their career.
Respectfully,
A College Student That Pays For Music