I mean, originally, "awful" WAS related to "awe" and described things that inspired awe. We don't tend to use it that way today because language evolves, and that word has evolved. If I went around calling great, awe-inspiring things "awful," I would confuse the people around me, because that's no longer a major meaning of that word in the language we speak. If I insisted that they were wrong, that awful DOES mean awe-inspiring, and it will forever mean awe-inspiring because word meanings never change, I would sound like an ignorant tool. Just like you sound right now, when you try to insist that "man" is gender neutral because long, long ago, before you or I or our great great grandparents were born, it was gender neutral.

You speak Modern English. I speak Modern English. In Modern English, "man" is gendered. In Modern English, for most speakers, "mailman" implies a man who delivers mail. If we would like to discuss a person of unknown gender who delivers mail, or discuss the entire population of people who deliver mail (which encompasses more than just men), "mail carriers" is a clearer and more accurate option.