Nobody seems to be bothering to define what is "canned", and what is not.

How big is the "pen". 5 acres. or 50,000?
Exactly how much country does a lion need to disply its natural avoidance behaviour?

Define "tame".
Really tame lions need to be taught to hunt and kill.

There are two issues here.
One is the sale of an animal that ios private property and bred for sale. No different from cattle, and arguing differently is complete Bambi'ism.

The second is the sale of the experience. If people are knowingly paying to shoot a tame lion, then shame on them, but that isn't a good basis for banning it. However if people are paying for a truly wild hunt and not getting what they paid for, then that is fraud and should be dealt with as such.

There should be a certain degree of "Buyer beware" in any such purchased hunt, but it isn't inappropriate to regulate such practices. Point is that nopt all operators will be the same, and we should not support attacking the good ones to get at the bad.