I don't think I could invent any type of work that is more perfect for offshoring/inshoring than IT.
1) Unlike manufacturing, you don't have to mess with physical inventory. This is huge. Shipping costs, and other supply chain costs, can be very substantial. With IT, everything is done over the internet. Perfect for offshoring.
2) Unlike manufacturing, you don't have to worry about special plants, or special equipment, special environmental regulations, or worker safety issues. Just use ordinary computers, and ordinary office space. Dealing with foreign regulations for building permits, and the like can be a nightmare. With IT, you don't have to bother with any that. Just rent space in an existing building. Even if you build your own building, you don't have to bother with all the special issues that go with manufacturing.
3) Unlike health care, or other fields, you don't have to bother with sort of special education, or licensing requirements. For example, we can import nurses from Mexico, they would not be qualified. Health care licensing is regulated by the state. Nothing like that to worry about with IT, legally, practically anybody can do practically anything.
4) No unions to fuss with. Replace all the IT workers you want with visa workers, then send the entire department offshore. No need to worry about union pushback.
Usually, when a group of people start screaming and crying about wanting "free trade," they actually mean that they want just the opposite of true free trade.
US employers routinely complain that they should be about to the hire the best bargains they can find, no matter where in the world those workers live. That would be "free trade," those employers constantly tell us.
The employer's assertions seems plausible enough, until you stop and remember that H1Bs are hired on very different terms than US employees. Unlike a US worker, when an H1B has gained experience, that H1B can not demand a raise, or threaten to leave. It is very difficult for an H1B to change jobs. The H1B can not freely market his/her skills. Frankly, that H1B is denied "free trade" when it comes to finding another job. And that denial of free trade, is exactly what US corporations want.