If they make it difficult or impossible to acquire through purchase … I think an argument can be made for surfing the high seas.

I don’t think this particular line of thought makes for a very good argument without more info. The other case makes sense. But for this one, people aren’t obligated to sell you things. If you own something sentimental or private to you that I want, you’re not obligated to sell it to me if I want it and I’m not justified in stealing it from you if you don’t want to sell it.

For ex: Think of embarassing photos of yourself, private letters between you and others etc.