I hadn't read the entire thread at that point.
As for your usage in specific you mentioned, I don't think you're being sexist, no. Nor do I think that you're trying to exclude women.
Thank you for clarifying that.
Every communication has an assumed intended audience. The author is supposed to consider that audience, and write to them. What does it say to the women in your audience if you stick to the male-generic? That centuries old rules of grammar are more important to you than showing they matter?
As I said, if a publisher thinks it'll attract more people by alternating "he" and "she" in the rule book, then go for it. I also said, though, I do find "she" in the general sense jarring while reading it, unless it refers to a specific person. It has nothing to do with tradition; I was just taught that "he" was general, so whenever I see "she" in the general, my mind immediately tries to connect it with a specific example. If none were offered yet, it's somewhat jarring.
I do like Celebrim's suggestion, though. Give alternating male and female examples, and tailor the "he" or "she" in the rule book to suit the examples given. That seems like an excellent middle ground for everyone.
People who read documents that only use "he" may react negatively to the writing because it feels male-dominated.
Which may actually be the case for some people advocating the sole use of "he"; however, when I'm voted for it, it wasn't to make D&D a "boy's club" or the like, as I've explained. A little bit more on my thoughts below.
As with all things offensive, it's in the eye of the beholder, and there's a bunch of reasonable people saying that using "he" only in modern writing can be seen as offensive because it makes no attempt to include the female gender in the writing when known modern style and language accommodates it.
See, the thing is, when I write "he" in my rule book, I'm not trying to include males, either. I'm just writing how I was taught to write. Would I mind a societal change? No, not really. It's not like I have a moral objection to it. I'd adjust, just like I did eventually when I regularly read the 3.X books.
In the meantime, though, I'd really rather the argument focus on "this feels more inclusive for women" than "it's sexist if you don't do this." That feels much less insulting and much more compelling, from my perspective. I totally get the first argument (which is why I've repeatedly said "go for it" to publishers), and I kinda resent the second argument (as it's untrue in my case).