It's not like people are just closing their eyes and trusting in leader. I'm part of that 40% (and probably substantially more given contemporary pollsters difficulty in reaching people like me [1]), and I think my rationale is quite sound. The fundamental reason is that we are creating an unsustainable system. When Germany chose to limit imports of Russian gas, they wrecked their economy. Many people, blinded by hindsight, wondered why they would have created such a dependency to begin with.
But that completely ignores the fact that literally every other nation, including the US most obviously, has excesses of dependencies on other countries, many of which we aren't friendly with today, and even more that we won't be friendly with tomorrow. Times change. An 'advanced economy' is a misnomer, if not an outright facade. Supplanting agriculture, real manufacturing, and other core aspects of your economy with e.g. advertising driven high tech discretionary industries creates an inverted dependency. People don't need iPhones or Google. They do need food, the zillion things in your home labeled 'made in China', and gas. If those 'lesser economies' chose to stop selling to the US, they'd destroy the country.
Offshoring all of these jobs also distorts the economy driving excesses of wealth inequality. Many of the jobs that used to lay between flipping burgers and writing code are the exact ones that have been hollowed out by offshoring. The fundamental problem we've created is that it's cheaper than make a widget half way around the world and ship it here than it is than it is to make it here. So how do we fix this? Tariffs are a blunt way to change this, but change it they do. The most probable outcome is that these providers will simply increase their prices which will, in turn, enable and motivate domestic competition and/or incentivize these companies to create onshore operations.
[1] - https://www.theatlantic.com/ideas/archive/2025/05/polling-20...