Whatever else may be said about Kratom -- and I won't dispute any of your personal observations about it -- I cannot find any instance in which the AMA has made any attempts to "ban" Kratom. Nor can I find anywhere that the WHO "prevented this action".
The FDA has pursued classifying Kratom as a Schedule I substance -- primarily on the grounds of its mechanism of action (which is quite similar to an opioid) and concerns about addiction, substance purity, side effects, etc. And there are genuine concerns here. Rather than the WHO (the dependability of which is always questionable in any event) attempting to "prevent" anything, it in fact pursued a "pre-review" of Kratom that could have been a preliminary to classifying it as a controlled substance. In Dec. of 2021, WHO announced that it would not be recommending a further "critical review". But this doesn't prevent the FDA (or the AMA, or anyone else) from doing anything. However you feel, it's good to get the facts straight.
Actually, Big Pharma would like nothing better (don't ask me how I know) than to be able to produce a commercial Kratom product. There's HUGE money in producing a commercial drug of this sort -- with careful production processes and strictly controlled outcomes in terms of dosage and purity so that doctors can be sure of what they're prescribing and patients can be sure of what they're getting (and how it may interact with other drugs they're taking).
There's a lot of confusion and dispute about Kratom. Right now, as with many "natural substances", it's the Wild West. And people can use it at their own risk. It's definitely promising, but I'd be really careful in taking it -- and trying to determine and monitor a uniform dosage and potential side effects and drug interactions.