[itishappy]

Their usage of "their" aligns with how English has been used for centuries (Wikipedia says 14th century), but more importantly the author's writing was the topic of discussion not their gender.

Policing other's pronoun usage is ideological, but that's your argument, not theirs.

[cubefox]

Obviously, that is: statistically, all involved here (the SCP author, the HN commenters, you, me) are men, so saying "he" is very likely correct. If by chance someone here is nonetheless a woman she will probably speak up.