How many of those papers studied non smokers' nicotine patch use?

Decades of research confirmed administration route affects addiction potential generally.

Injected amphetamine is highly addictive. Many people who ingest amphetamine most days forget it some days.

Where do you come up with your 'thousands of peer-reviewed papers'? The 'some webpage' is by Gwern who usually does a pretty good job surveying the literature. I'd actually trust him over NIH, WHO and FDA here (because Gwern's smart enough to take their opinion into account where it makes sense, and also look out for their biases; not because Gwern's magically smarter than them in general.)