That's the thing about language though. It is because you choose it to be so. Other people choose for 'guys' and 'dude' to have a different meaning.
Collectively we decide who wins. Nobody is right or wrong in the present because it's a never-ending battle over an idea. Words change over time - always have and always will.
You can only be right historically in context. 'Guy', _historically_, does not mean 'man'. What it means now is your interpretation. You should not get so bent out of shape because other people disagree with you.
There is an inherent problem with basing gender-politics around the meanings of words. How do you deal with people coming from languages that do not have gendered pronouns that are trying to translate their language into English? Do you beat them over the head for how wrong they are (before you say no, I've seen it countless times)?
Also hey, guess what. 'He' has seen use as a gender-neutral pronoun well into the 1960s.