If the objection were to parenthood, which is to say if nurtureboard or parentboard were similarly offensive, then I agree this would have been a stupid stupid choice.

The problem is that you had a motherboard and daughter boards, those were the accepted terms, and never fatherboard or son boards, never parentboard or child boards. Why were they gendered female in the first place?

Because they had “female connections,” which is to say their use is in plugging pins into their sockets.

Obviously that is a sexual analogy that did not age particularly well, this idea that a motherboard is the motherboard because you shove stuff into it. So people started replacing with mainboard because it makes more sense...