Couldn't agree with you more.
Which is why shooting accurately is so important.
If someone only sees quick and successful kills, with 6mm, 243, 223, 30-30, etc then the only conclusion they can come to is they work extremely well.
In the same way that someone who sees animals run off, when shot with a 300, 308, 338, etc can form their idea of how they don't work well. Maybe they do work okay, but the shooter sucks.
Me, I would bet my money on the best shooter, not if they were carrying a 243 or 338.
When I hear/read stories about people who rarely shoot, don't even know how to 0 their rifle, much less properly account for longer shots, and adjust accordingly, those are the unethical hunters in my opinion.
If the government wants to impose rules and regulations, how about instead of cartridge, they make it on proficiency.
To get your tags annually, you must first every year show up on designated days at a range. Upon arriving you have brought exactly 20 rounds with you, and at 100 yards must hit 4 out of 4 targets the size of a quarter. At 200 yards 4 out 4 twice the size of a quarter. At 300 three time the size of a quarter 4 out of 4 times. And the same thing at 400, and 500 yards, where the target is only 4 and 5 times the size of a quarter, 4 out of 4 times. If you miss once, you'll be allowed to retest after 30 days. That qualifies people to hunt up to 500 yards only. If someone wants to qualify for longer ranges, they can try, but the targets no longer get larger, or else the error factor is too huge. They must hit a target 5 times the diameter of a quarter, 4 out of 4 times, at the range they wish to qualify to hunt at.
5 times the diameter of a quarter is pretty large, if they cannot be accurate on something that BIG, well then they best get practicing. It would also assure their rifle is properly sighted, and they have a clue about bullet drop, windage, etc.
Dude A, who has a 243, and is a good shooter, is a vastly more ethical hunter, than Dude B, who can't shoot worth crap but has a 338.