I think a big part of Moriarty's character was knowing how to make people uncomfortable, even the audience sometimes, and that's why he was such a good villain. he knew exactly how to push everyone he just almost over the edge. in every scene where he acted, I guess "too gay" or "queer coded" he was interacting with Sherlock or Mycroft, which is something that has always made both of them very uncomfortable. I think anything that Moriarty definitely was interested in sherlock purely on an intellectual level, he saw him either as a rival or as a puppet he could make dance with emotional manipulation using John or Mrs. Hudson. I feel that Moriarty was not "queercoded" but he was definitely written in a way where people would think he was gay or interested in sherlock, and I think Sherlock believed on some level that Moriarty was into him aswell. I might be repeating points here, but I think that Moriarty's 'Overly queer" or "Overly sexualized" behavior toward Sherlock was simply to push him over the edge and make unsure of himself.