Apples and oranges.
It increases disparity and reduced wages for Americans within the US labour market.
It reduces disparity by sending formerly high paying jobs over to third world countries, marginally increasing their average wage and wealth while reducing our own.
“marginally increasing their average wage and wealth”
Marginally?? Go ask the Europeans, Japanese, Korean, Taiwanese, and now Chinese and Indians how marginal a change it is from the ‘50s to now.
As for decreasing our wealth, you need to measure not just the income but also the expense. Generally speaking, prices on goods that are imported has gone way down (compared to when they were produced here), so our net has improved even if our wages have not gone up much.
As capitalism, competition and trade expands worldwide, it is inevitable that wages and standards of living across countries will tend to equalize.
Also as cheaper labor is brought into production, prices will tend to go down. That’s good for us as consumers. However since we’re all both consumers and producers, it puts a lot of competitive pressure on us as producers to produce more and better for less. That part is not always pleasant.
To avoid social disruption and unpleasantness this type of globalization has to be done gradually, otherwise you’ll get social unrest from people that have been displaced by too much and too sudden job migration. So some protectionism is warranted, but too much is counterproductive.