There now that I got that out of the way. Calling a mixed group of people 'guys' is basically erasing the women in the group. Male pronouns, etc are the default for people, but are homo sapiens made up only of men? No. When a lone woman is walking down the street do you say 'hey, look at that guy?' Probably not because guy in the singular is considered male gendered, so why does adding an 's' to it suddenly make it gender neutral? Ooooh, surprise: it doesn't.
I know I am talking about the subject that makes men more angry then a lot of the other things that come out of my mouth. (Surprise, surprise). I guess I should be grateful or happy that they're basically calling me a guy. Because it's such a compliment to be called a guy, right? Um, no thanks. Being female I see nothing less or diminished about my gender, and I sure as hell find it insulting that I should not complain when guys call me a guy. (Just do a little experiment: try calling a mixed group or a group of all men 'ladies' or something equivalent. They find it insulting and get really uppity about it. How dare I call them something feminine! How insulting! So why can't I be insulted again? Oh yes, patriarchy.)
Because men have been in charge of creating the language male gendered terms have been defined as 'positive' or 'neutral' and all things feminine have (surprise, surprise) been defined as 'negative' or 'other.' So what? You say-it's only words. Only. Words. Think how silly that statement is. Words define our reality, they are the building blocks for most of our communication. They have meaning and when you use masculine language you essentially erase over half the population, and the patriarchy has made it easy to overlook women. Not that it sees us as fully human anyway. Observe what sociologists say:
The Sapir-Whorf hypothesis suggests that, as we learn a language, our sense of reality is shaped. Therefore our attitudes of what is masculine and feminine are taught to us mainly through our process of learning a language. Language then stays as part of culture long after its first speakers die, and its changes often lag far behind other social changes.(From here.)
Still think that I'm grossly misled? HA! I laugh at you, there is so much study on this topic that you telling me that usiing anything masculine as gender neutral makes me laugh. Here's a nice handy dandy example:
If you write with nonsexist language, you write to represent with fairness the gender identified in many words. Gender-fair language minimizes unnecessary concern about gender in your subject matter, allowing both you and your reader to focus on what people do rather than on which sex they happen to be. For example, the practice of using he and man as generic terms poses a common problem. Rather than presenting a general picture of reality, he and man used generically can mislead your audience. Research by Wendy Martyna has shown that the average reader's tendency is to imagine a male when reading he or man, even if the rest of the passage is gender-neutral. Therefore, you cannot be sure that your reader will see the woman on the job if you refer to every technician as he, or that your reader will see the woman in the history of man. On the other hand, replacing every he with he or she attracts even more attention to gender and defeats your purpose. This predicament merits special attention in scientific and technical writing, where any ambiguity is unacceptable. (From here.)
Now change write to speak/write. Words are powerful, the masculine is not gender neutral, and if you call me a guy I may very well scream.