From the linked Article:
imports of opium (to the United States) increased from around 113,000 pounds in the 1840s to 1,500,000 pounds in 1909
Was that anywhere near China levels?
More interesting information from that linked article:
"The opium rush was at its most prevalent during the 1880s and 1890s, which coincided with the rise of the temperance movement."
The law of unintended consequences has always applied in spades to wars on substances.
"the Smoking Opium Exclusion Act banned the importation of opiates used purely for recreational use.
"However it's unclear if this act was part of anti-Chinese backlash as it was thought Chinese men were luring white women to have sex in the opium dens."
Calls into question whether there was a significant problem with opium as such.
No it wasn't, and that's because it was never allowed enough time to get to that level. We stopped it before it got that bad by outlawing these drugs.
More interesting information from that linked article: "The opium rush was at its most prevalent during the 1880s and 1890s, which coincided with the rise of the temperance movement."
Post Civil War people were becoming aware of the dangers of drug addiction. Yes, several hundreds of thousands of former soldiers addicted to drugs would tend to make people aware that the stuff is dangerous, and so would therefore initiate a temperance movement to stop it.