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?What is the policy on discussing OSx86 or Hackintoshes?
- Technically valid answers that raise questions of moralityTechnically valid answers that raise questions of morality
- Policy regarding questions related to unethical or “shady” practicesPolicy 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.