Because the two men (or two women) could theoretically be producing more humans themselves.
So how would executing them help?
Also, many homosexual couples have children, either via adoption or using a sperm donor/surrogate mother. So that isn't really an argument against it.
Besides, the human race is reproducing too much already, and if the birthrate continues exponentially, eventually we'll wipe ourselves out by over-population. In some countries, having more than one child is either illegal or you require a special license (e.g. China), and in a few others couples are offered incentives (land, money, etc) to have few or no children. It could therefore be argued that those homosexual couples who don't have children are actually making a contribution to the human race, especially if they are doing it of their own free will and without incentive
.
BTW Of course there is nothing wrong with homosexuality ask your local catholic bishop. I mean if a bishop does it how can it be wrong?
I really do hope you're being ironic there. If not, you do realize that statement condones child molestation, right?
EDIT: incidentally, if we follow the very letter of the bible, then apparently incest is perfectly acceptable
. After all, the children of Adam and Eve had no-one else to mate with but each other.
And did you know that "Thou shalt not kill" is actually a mistranslation, and it should actually be "Thou shalt not murder"? A pretty subtle difference, but one which changes the meaning quite considerably. It makes you wonder how many other words and phrases in the bible are mistranslated from the original source. There's plenty of evidence of later additions too; I remember hearing that there was an earthquake in Israel something like 1,600 years ago, which sunk a chunk of land into the sea. Apparently a certain seaside location visited in the Bible is along the "new" stretch of the coast, rather than where the coast actually was at the time.