No money is gone with a credit card until you pay your statement. Your statement does not include AUTH charges, only completed charges, so there is in fact no money gone. Your credit limit is decreased by the amount of the auth, but that's not money, it's credit, and those are two fundamentally different things. Also, some card issuers allow auths above and beyond the actual credit limit, and overage fees only apply to charges actually processed over the limit - your card issuer terms/conditions should spell this out.

You can rolleyes all you want, but there's a big difference. From the NY Times:

"Federal law also protects you if you need to dispute charges on a credit card, but not if you use a debit card or other forms of payment. If you paid cash or used a debit card, the retailer already has your money. So you have a lot less leverage, and there’s no guarantee you’ll get that money back. But if you pay for something with your credit card and aren’t happy with the purchase, your card issuer can legally withhold payment from the retailer until they resolve the dispute, and you won’t be charged."

No, there's a risk assessment involved. My gas station holds $80, regardless of what I actually pump, because credit card fraud at gas stations is very high. It's likely the same with UA - taking global credit cards, matching global addresses, for a product that requires them to do significant legwork to positively identify the purchaser and traveler. They're also dealing with high-value items, so they auth the full amount to ensure that it's available when the transaction closes (vs. the person being over their limit by the time the transaction closes).

Except that the purchaser of the ticket might not be the traveler, which could lead to more significant customer service interactions (which are costly) down the line, especially if someone "brokered" the tickets through a stolen credit card, e.g.: A steals the card, then acts as an agent for B, taking money from B and using the stolen card to make the purchase. B gets a ticket, A gets the money, then the airline finds out the charge is fraudulent and revokes the ticket. B, unknowing, shows up to the airport to fly, only to have a canceled ticket and no idea why.

Your cancelation of the booked portion of your trip was "easy" because the airline could clearly see the problem. The problem here isn't the cancelation, it's that UA and ANA's systems are apparently miscommunicating, leading UA to sell a ticket that ANA can't honor. That will get found out, and the purchaser will get notified, but not in a 30 minute window, especially given the irrops and re-bookings going on right now with the newest incarnation of a snowstorm in the northeast. Even 24 hours may be too short a window at this point. It's good you caught it, it's good you brought it to UA's attention, but given the scope of the problem (one flight on one partner) it's unlikely to be a major business impediment at this point.

Rebook and get on with your life.

Only on debit cards. And only with some banks.