1. Are guys like Friedman and Sowell right about global trade,

If you assume all cows are spherical and don't weigh anything and don't interact when they collide.

Where it butts up against the real world is where you lose the ability to produce everything at home in case of war or hostile foreign actors. But that one is obvious. That flaw is well explored.

Another place it fails is when you fail to consider conglomerates or nations acting 1 industry at a time to advantage themselves. The Chinese for example will happily subsidise orange farming, block your oranges from sale in their country, take advantage of what is basically slave labour to create a huge surplus of their oranges and then dump their oranges on your shores, killing your local farms. Good for consumers that year right? Well now your local orange farmers are bankrupt, and maybe china even bought that land up. Either way, now china controls the market. It might remain somewhat cheaper because they still have that low wage back on the mainland and a lot of investment in mass orange harvesting, or they might be able to ramp up the prices to higher than they were. Either way, China is winning. If prices remain lower, your local farmers continue to be unable to compete and you lose that local knowledge. But even if china gets greedier and ramps the price right up locals can't easily just start up another farm to compete and take advantage of the now higher prices because of a high barrier to entry and lack of knowledge AND the best spots are all already taken and china can always just do it again for one year and kill the new farms. And then you move to the next food product, then the next.

You cannot have free trade with china. But what I just talked about doesn't apply just to china or other nations with that co-ordination. Bigger companies will do it too. Supermarkets will loss-lead, selling bread and milk on the cheap to get you in the door and putting bread at the front to have the smell draw you in. But this is a manipulation, an advertisement campaign that kills your local baker who cannot do the same with his prices because the bread is all he sells and knows. Letting foreign companies who do not have any loyalty to their local area is the issue. Free trade inevitably means making your locals compete against foreigners with shit wages AND who don't care about your local long-term situation AND who are happy to co-ordinate in ways that destroys your local industries in an 'unfair' way, one that isn't simply about providing a better product at a lower price. Them being able to leverage their profits from one arm to run another arm at a loss for a short while for various reasons, to kill competition so they can later have a monopoly or as an advertisement is a fundamental flaw with free trade. Whichever the reason, you're now down a local family business for no good reason.

A third reason against 'free trade' meaning no tariffs is that tariffs are the least bad option in terms of taxation. What are your other choices, given even a minarchy's need to tax at least a little bit? Taxing productive work with an income tax? Taxing the successful and productive by taxing profits? The theft that is inheritance and wealth taxes*? Sin taxes? land taxes?Resource taxes? Well, ideally resource taxes actually, if you're in a situation like Norway (or like Australia SHOULD be) is in, you'd be able to not tax anybody doing anything productive, but effectively just 'sell' the resources under the ground. But the next best option after that and some sin taxes which won't cover your needs, is tariffs. It protects local industries, as compared to a local sales tax it in effect only hits the goods from foreigners, and is easier to collect at the gates coming in rather than burdening each and every business with taxes to track at each little transaction and gumming up all trade between people.