Others are replying, but I don't know that there's any idiom needed. Raising the price to whatever people willingly pay is just being a merchant.
Is this the market-economics version of political correctness?
I don't think it is. Political correctness applies when people feel they can't plainly say something that's true. In this case, using "price gouging" adds nothing to the statement that prices are high except a sense of outrage, and my response was merely that I think the outrage is misplaced.