I always try to remember that although Ross and Jimmy are close friends, one cannot assume Ross' opinion mirror's Jimmy's. That being said, I agree with Ross' particular assessment of this situation. Sure, he could have said it more politely, but to me Jason should have let things go when the reunion didn't happen. Honoring his father is great, but basically trying to make it a pseudo official Zeppelin thing when all it is is a tribute band is wrong and it seems to me he is milking his father's name instead of resting on his own laurels.
That being said, I am sure Jimmy doesn't mind the name dropping that Ross does. He probably appreciates the attention. He and Ross have been close friends for years and if he didn't like it, he would have most likely told Ross to stop it. Besides, I enjoy Ross' diaries as another way to see what Jimmy (and other artists that I like) are up to when things are quiet. And let's face it, things are a little quiet for Jimmy at the moment.