Except even that statement would likely not be true unless all of your materials can be sourced domestically within the US.

As there are few countries without tariffs in the US, moving your manufacturing there would actually increase the amount of tariffs you are paying instead of reducing. No matter which way you look at it, his statement is incorrect and as the other commenter noted, it's either on purpose to mislead his base, or simply the result of his lack of understanding of how tariffs actually work.