For example, back in the 70's with price controls on gas, people hoarded gas. All that nonsense stopped literally overnight when Reagan repealed all gas and allocation controls.
Anti-gouging and rationing prevents that hoarding, as long as they are implemented intelligently.
That's the theory, but the practice is the opposite. When people know they'll be able to buy something, they have little incentive to hoard.
Additionally, since the price is kept manageable, everyone who needs the items will be able to afford them.
If you don't combat hoarding and price gouging, people will panic buy, because they know the price could increase at any point, and because the want to get ahead of the hoarders. Now they become the hoarders.
Libertarians fail to understand why businesses often do not extract the maximum possible profit from the market at all times, because they do not understand that commerce is much more complicated and human, and not solely based on supply, demand and price signals. They do not understand the business/consumer relationship. They do not understand morals and ethics, and why businesses would want to maintain a good relationship with the customer base, instead of fleecing them to the maximum possible extent.
It's generally, libertarian/ancap circles aside, viewed as immoral to exploit the essential needs of people; also it incentivizes hoarding which puts the availability of critical goods even more at risk. We have seen this in action with loo rolls, hand sanitizer and non-perishable food in the recent crisis, and with people actually getting punished for it: https://www.nytimes.com/2020/03/14/technology/coronavirus-pu...