Karma made sense!!

So I came to a realisation when I was bathing..., yes..., in the toilet..., here goes:

What goes around comes around right? (Something along that line)

So I believe in this thing called karma, they were saying when you do a bad deed, you will accumulate bad karma..., so I supposed killing is a VERY bad karma..., not only killing humans, killing animals are counted too right? (That's why monks are vegetarian)

Decades / centuries ago, there were not as many chickens / pigs / cows, etc. Human started breeding them and killing them for food, creating bad karma for themselves, probably earning them a few lifetimes of "reincarnation as animal"..., then demand increases, supply increases too, means..., more people killing more animals!!

[This was stuck in my (draft) for years]