The "born out of violence" line for half-elves and the similar phrase for half-orcs is a step up from the 3rd edition rules where it was apparently felt necessary to suggest that all half-orcs were born of rape. But it isn't necessary and including sexual assault into the game doesn't add anything, so why do it?
I realize that some people feel it is almost a requirement and there are at least a dozen folks who are about to type "oh yeah, well the game has murder doesn't it?" Which somehow implies that without those sentences the game will break verisimilitude or be far too happy and huggie-bear. For these gamers I suggest using the space you save with the cut and use it to draw in skulls or something.
The only birth histories that we typically care about in these games is the PCs and a few major NPCs. That's it. If you get right down to it a hafling could be born of sexual assault. The overwhelming amount of time it just doesn't come up. How many encounters run like this:
The PCs walk down an alley to meet their contact, suddenly a half-orc assassin jumps out!
PCs: You're no match for us, you murdering half-orc bastard!
1/2 Orc: ... that's ... that true ... I never knew my dad. Oh woe! Where is he now, that man who left me so alone? Would I ever have joined the Loathsome Death Guild if I had known the gentle wisdom of a loving father? And poor Mom! Would it have been so hard to look past my face and see not a reminder of that tragic night, but instead a young boy in need of a mother's embrace? *sob* *sob* *sob*
It isn't needed. Its stupid to add it in. Just cut it.
If people complain just point out that we already have two pictures (pg 36 and 40) of a surprised woman with her back arched, legs apart, and mouth open. Neither of them are wearing all that much either. Isn't that enough?