Veganism is all very nice but its a lifestyle choice fashion only brought about because living standards are high enough to allow such luxury. Humans put under starvation stress will revert to eating just about anything. Just as true is that the eating of the quantities of meat that we do now is also a result of affluence.
Our natural diet should be mostly grain, fruit, nuts, berries, and vegetable matter, with a small part consisting of meat. Similar to bears, with the odd beetle and seafood dish thrown in. Unlike bears we do not need to hold huge fat reserves to hibernate the winter.

The improvement in modern 12ft/lbs air rifle's virtues should be sold more that the range for pest control hasn't changed, its still farmyard ranges, maybe adding no more than another 10m with practice. That more precision should allow us to be even more humane with our delivery and be applauded for that fact. However, for target shooting this improvement in accuracy allows longer range target shooting to be done just for the fun of it all, but it is not a reason to extend the practical hunting range to the same extent. The effective, humane, practical hunting range remains virtually the same as its always been.
An individuals hunting range is and will always will be limited to an individuals ability to deliver with confidence the pellet, whatever calibre, into what is a very small lethal kill zone.

A good sportsman will practice, test, and practice again, until confident and sure. Realistic of their abilities and show restraint by staying well within those abilities. Its the least one can do to show respect for one's quarry.
If you are not happy with 12ft/lbs for hunting use then don't do it. That is an individuals call.