I'd dare to respectfully dissent, Justin. Many professional composers, especially in tight time budgets, hire people to orchestrate their ideas for them. This is, at least according to the books I have read, quite common in the film industry and, according to those random e-mails offering to orchestrate my music for me (yeuch!) I get every other month or so from random person somewhere, it's a rather far reaching one too. I think the reason he calls himself that is that it is in Orchestration that he does MOST of his work, but not all, which he mentions in his 50th birthday video (titled ironically "A Composer Turns 50").
Yes, Thomas Goss is rather opinionated (if not VERY), but he has some very good points and years more experience than most people I know. He also has studied scores religiously and seems to understand the elements of orchestration as well if not better than the principles of composition. For that reason, I think he has a bit of a right to be opinionated and authoritative (his video where he berates Bernstein for being this way made me laugh a little).