The effect of Smoot-Hawley, most economists now acknowledge, was very small -- although it was real. But it was insignificant compared to the liquidity crisis caused by the central bank, and the economic circumstances were entirely different.
At that time, the US was a creditor nation. The initial liquidity issues were caused by the inability of debtor nations to meet their obligations to us.
Smoot-Hawley was simply stupid, given that at that time our balance of trade deficit was negative [we were a net exporter.] Net exporters do not erect trade barriers.
In ordinary circumstances China's monetary policy would amount to an enormous tax on her people, the benefits of which are provided to the countries she exports to, and it is true that we do accrue an enormous economic benefit from that. The problem is, that unlike the America of the late nineteenth to mid-twentieth centuries -- which regarded itself as at war with no one -- China is at war with us, and is using the valuation of its currency to destroy our industries [and, although most people don't realize it yet, it is positioning to destroy US agriculture as well.]
Said more eloquently then I could.
The chief point is what you said: China is at war with us, and they play for keeps.
Good for them. Least they have a nationalist outlook.
But so should we, and getting moderately cheaper iPads is not a reason to lose the country.