If your going to eat it you should be willing and able to kill it in my mind. I kind of understand your sentiment, but when you really look at it it is hard to justify. I'm willing to do it, but what about someone who is too squeamish - not allowed to eat meat? And what do you mean by "able". Time? Knowledge and expertise? What do I do, approach a farmer and say "can I kill one of your pigs?" And what would I do with a full butchered pig? If you're going to use a knife for the butchering, do you need to be willing and able to forge one?
If you're going to use a web forum, you should be willing and able to program one.
A web forum or knife is not a living feeling being (I think) It does not give up it's conciousness for your use and in fact is not consumed (Granted this is arguable with the knife as it is slightly consumed). Yeah I think that at least once in your life, if you are going to eat pigs you should approach a farmer or a friend who raises them, and ask if you can kill one.
Able... well I suppose physically unable folks might get a pass as long as a true willingness exists. But it's hard to say 'I am willing to kill this animal' and really mean it if you are never presented with the opportunity. Doesn't have to be a pig, could be a chicken. even catching a fish is good. It's the awareness that this being is alive and vital and because of your choices and actions it will no longer be that. If you buy a piece of cow in a styrofoam container you have still caused it's death but you have not experienced that death in a real way.
If you are too squeamish to kill an animal then maybe you should reexamine your feelings about eating them. That is actually my point. I think that alot of folks who eat meat would not if they had to kill an animal themselves. The idea that it is moral to eat and animal but not to kill one is strange.
Anyway, it's not about 'allowed' and 'not allowed' I am not (yet) the king of the world so y'all can do what you like. It's more a philosophical stance.
and just to head off one argument, I am aware that the plants I cut out of my garden are vital beings and try very hard to keep that awareness with me as I pick, cook and eat them. I even think about it when pulling weeds and certainly when picking slugs off my tomatoes and squishing them.