Why does the US textile industry lose jobs the foreign countries?

Labor intensive production is cheaper to do in countries with lower pay rates. In the US, there's a minimum wage, other places there isn't.

Some other textile tasks, like dyeing(which is often toxic), is cheaper to do in places with less environmental restrictions.

Cheap imports can force U.S. companies out of business.

Foreign countries often accept lower salaries and poorer working conditions, meaning stuff can be made cheaper there.