I have the opposite of this. My primary email address is hello@firstnameMIlastname.com. But there's another guy who has the same name, and doesn't include his m

I have the opposite of this. My primary email address is hello@firstnameMIlastname.com. But there's another guy who has the same name, and doesn't include his middle initial in his domain. It doesn't appear that uses hello@, so maybe he doesn't get my mail, but there have been many times where someone insists they've sent me something, only for me to find out they didn't include my middle initial and were sending stuff to him, despite the fact that I sent them my email correctly. Why didn't they just copy and paste?