It is absolutely a double standard. Male friendships are common yes, but not like female friendships. Things like two males hugging, being touchy with one another or sharing all of their feelings are seen more sexual and romantic in nature than when females do it. Whenever see it with men, there is almost always a character who questions if their relationship is platonic. Holmes & Watson are the most popular bromance in our culture and even there, the character Mrs. Hudson can't imagine their relationship is platonic. She bases this solely on them being bff's living together.
We can find this same double standard in real life. Take this article for example:
https://www.succeedsocially.com/oneononewithguys
This is from a popular internet social guide on how to make friends. The author talks about how men are more likely to get "date vibes" from just hanging out one-on-one with other men.
Anyways, back to Johnny Storm...I think Johnny can be gay/bi and still have a platonic friendship with Peter. But not everyone seems to agree, including the people most on board with the idea of Johnny being gay/bi.