Nobody has to justify the price of something to anyone but themselves...if I want to spend $2,000 on the '15 Macbook, that is my business...maybe it is worth it to me for some function it has, or maybe I just like the way it looks enough to spend the money (for clarities sake, I do not feel it is worth the cost either, FYI).
There is no "issue" with the cost, you simply don't feel it's worth it...and that's fine, don't buy it. Lots of people feel otherwise, and they have bought one.
And the '15 brings plenty of "new" things to the table that even the current MBP's don't have...battery efficiency, form factor, interior design which renders cooling fans irrelevant, the new keyboard, haptic trackpad (though the most recent MBP did get that), and I'm sure I'm missing a few things. And Apple priced it where they felt it was appropriate within their line of computers...don't agree? Congratulations, you've made a consumer decision...doesn't mean there is anything wrong with the pricing point, it just means it's not for you.
I'm not sure what is hard to understand about that. I personally don't feel that Mac Pro is worth the money Apple asks for it, but I don't sit here and complain that Apple is doing something wrong by charging that...it is what it is, and a lot of people buy them for what they ask, so why wouldn't they?
Your issue is that you approach this strictly from a consumer stance, so your priorities and your opinions of what is "fair" is kind of a moot point, because you're not in the market of making a profit off these products.