I think Columbo represents a kind of masculinity that is very attractive to a lot of queer people. I see a lot of love from trans men in particular, myself included. First of all, I think you can start with Peter Falk himself—He’s a short guy, he has a higher voice, and a lot of trans men can probably identify with these or other traits of his.
Falk characterizes Columbo as undeniably masculine, but unconventionally so for his time. He has no issue being openly affectionate with other men. He likes sports, beer, and Westerns, but he also likes flowers, cooking, and shopping. He is logical yet intuitive, strong yet yielding, stoic but never emotionless. He does not adhere to gender norms, he dictates his own.