That's also a reflection of you and/or environement. I carry various types of bags. One is a MaxP. Another is a small leather bag that looks as non-tactical as possible without looking like a woman's purse.
In California, I am not unusual looking. I have been carrying a man bag for years, and I have asked various people. Everybody assumes I just have a lot of stuff to carry. However, when my family visits from Lousiana or Texas, they immediately ask if I'm packing. It doesn't matter what bag it is.
Anyway, going without a man bag is just super inconvenient for me at this point. I don't know how other guys do it, unless they enjoy wearing baggy, frumpy clothing with lots of pockets. I personally prefer my clothes to fit well on my body.
That's kind of the point of greyman. Don't stick out in a particular environment. Certain patterns and styles of clothing and gear only blend if they're part of a limited demographic. I.e. Tactical stands out unless you're a teenager or active or ex-military. A leather messenger bag/satchel is a non-entity unless it's distinctive (i.e. Ferrari red) in some other way.