This is horrible for the EU. They now have a huge economic disadvantage over the US.

Yeah, that IS the point of tariffs. It's also a very basic understanding of global trade.

When you buy something from another continent, you're already paying WAY more than when you're buying it nearby. So why would you do that? Well, in most cases, it's because you can't buy it locally.

Global trade is global because lots of products aren't produced everywhere. Much of what the EU is selling to the US is stuff that the US either doesn't make, or doesn't make in enough volume to cover its needs. And vice versa. Trade balances group products together, so it doesn't usually show, but you can sell me a billion worth of ball bearings, and I can sell you a billion worth of ball bearings, and if I tariff you heavily, that won't change at all because there are a thousand different types of ball bearings.

Now, traditionally, a tariff can promote growth of local industries, but you can't just make a new factory in a few weeks, months or sometimes even years. If we assume the industry reacts immediately, it will be many years before simple factories are up, and decades before entire chains are reproduced.

And the industry won't react immediately, because nobody trusts that these tariffs will stick. You need to put a tariff in place for decades to be effective, and Trump can't even stick to a plan for months.

So in practice, just having short term stability is worth it. Plenty of industries are actively holding off on large purchases because it might suddenly have a 20% tax hike on top. Or lose one, or god knows what the orange idiot does next that will destroy your profit margin.

Because again, they're not buying abroad for a small advantage, they're doing it because that's where this product is made, and they can't buy it elsewhere.

Strike breaking

That doesn't remotely apply. Assuming International Trade is like your personal bank account is a Trump level misunderstanding of economics.