It's a red flag? Come on, if I wear a suit it's because I want too and has no impact on my skills as a software engineer.
Being hyper judgemental about the clothes people wear isn't productive
Being hyper judgemental about the clothes people wear isn't productive
However, like it or not, it is a signal because it means you deviate significantly from the mode of the distribution. And a sober application of Bayes suggests that if anything, all else equal that signal is a negative one.