There is no general Stack Exchange policy. The general trend is to only ban clearly illegal content. In other words, by default, if it's a grey area, it's allowed. See these threads on Meta.SO:
- What is the policy on discussing OSx86 or Hackintoshes?
- Technically valid answers that raise questions of morality
- Policy regarding questions related to unethical or “shady” practices
So the decision to allow Hackintosh questions or not is up to the Super User community. For a long time, the only answer to Are “Hackintosh” questions allowed? was BinaryMisfit (formerly known as Diago)'s vehement no. Note that although BinaryMisfit was a moderator at the time, his being a moderator is not what carried the decision: what carried the decision was the community consensus.
Later Arjan posted a defense of Hackintosh questions which now has the score +30 to BinaryMisfit's +19. So the SU community no longer has a consensus. There is a weak majority in favor of allowing Hackintosh questions, getting to a point where a change in moderation policy should be considered.
Note that Arjan's answer should not be deleted, since it represents the opinion of a part of the community.
Disclosure: I personally support Hackintosh questions, but this answer is not in defense or support of Hackintosh. It is about Stack Exchange policy.