Let me let you in on a secret -- males are actually really easy to pair up
if they have enough room. Unfortunately, as far as I know, there are really only 1-2 pet store cages on the market that have enough room. So you put two pigs in this tiny cage, they fight, and then they go "Welp, he doesn't get along with males!"
It'd be like sticking two male rats in a 10 gallon aquarium and then being surprised when they squabbled.
We are as gods to the beasts of the fields. We order the time o' their birth and the time o' their death. Between times, we ha' a duty. - Terry Pratchett.
"Men have forgotten this truth", said the fox, "But you must not forget it. You become responsible, forever, for what you have tamed. - Antoine de Saint-Exupéry