Two points.
1. Drugs push themselves by acting on receptors in your brain in such a way as to induce craving.
2.Even if drugs were pushed in China, (which they were.) how are you going to stop pushing of a legal product? Drugs and pushing are inseparable.
The very notion of "free choices" becomes blurry where drugs are involved. Drugs act directly on the decision making portion of the brain, and at some point you can no longer distinguish free will from chemically induced desire.
The only people who can truly make a "free choice" regarding drugs are those who have tried them and had the will power (or lack of effect) to give them up. A huge swath of the populace simply cannot do this.
I have quite made it clear over years that any kind of ban aimed at the inanimate will serve only as a pitiful, dirty band-aid.
Even the bible says so.
No, not even a drug pushes itself; attitudes about their use push them, or in contradistinction keep them to sane purposes such as medicinal.