There are two different arguments being made here. One, IS Johnny bisexual based on history. Two, SHOULD he be written as bisexual in the future. Outside of Daken (and I haven't read that story), there is little actual evidence, but plenty of scenes that would fit the profile. I agree that going over Johnny's near 60 years of stories, his character screams hetero. The argument I'm making is that to better reflect the diversity of people and the lack of diversity in early 1960's characters, Johnny needs some expansion in that category.