Tariffs are a tax on the country that imports. That's not fear mongering, that's just reality. The tax isn't applied in the exporter, the intention is to discourage importers from using those nations. The problem is, China controls manufacturing. If they use Mexico as a backdoor, that's just to bypass higher tariffs, but isn't actually discouraging the importation of Chinese products, you're just adding a proxy into the mix.
Think about this: let's say I usually sell tomatoes to John for $1 each, but then the govt announces that they will apply a 50c tariff on top of every tomato John purchases. I still sell the tomato for $1, but as soon as it hits John's hand, he now needs to front up $1.50 in order to receive it. At this point he could look to buy locally, but they charge $2, so it still makes more sense to buy from me even though it now costs him more, but there is now more incentive for him to buy locally.
If I want to minimize my risk of losing John as buyer, I could sell my tomatoes to Suzy for $1 with the intention of her selling to John. There's still a mark up, let's say Suzy charges 10c for this service, and a smaller tariff of 20c, it's now $1.30 instead of the original $1.50, so there's more incentive for John to continue to buy my product, even though it now comes from Suzy.
not a single original thought.