I haven't read your other posts so this is just my two cents :P
I agree that there can be a big disparity between written and verbal communication, misunderstandings do happen.
In a post, I think it was in "Coming Out", someone made a statement about parents not needing to get so upset about their children being poly if they "still got grandkids out of the arrangement" (I'm not quoting word for word, just summarizing in my own words). A seemingly innocent generalization that irked me. This is likely because my own family has made insensitive comments about my infertility and have questioned my decision to be childfree.
What it comes down to is that I "own my shit". The person who made that generalization didn't know me, didn't direct it at me, and I can be sure was not out to offend me. Me getting offended was my own reaction that I'm responsible for and I know that it certainly wasn't worth getting into a debate over. If I see a post or discussion with someone making broad generalizations that I feel strongly about, I may jump in, even just to play "devils advocate". That applies to me too, as it can be quite cool to see a side of things I never considered. I may get irked by things, but I usually let things slide when I can see there was no harm intended. Do most parents want grandbabies? Sure, I would say most parents expect their kids to have kids. Is that fair? Is that right? Therein lies the debate and dangers of generalizing. Generalizing puts people into a "one size fits all" when it's impossible to do that 100%, you're inevitably going to leave someone out.
I don't mind pointing out a generalization if there is that opportunity to get some growth from it, something learned, just a cool conversation. I would opt for a discussion rather than a debate. However, sometimes you don't know you've offended someone until the "deed is done". I don't know if it's always worth expending energy getting upset over generalizations. It's kinda like some people getting a kick out of correcting other people's spelling :P
I didn't read your posts so I don't know exactly what you may have said to offend people. Maybe you were abrasive or maybe they were sensitive, maybe a bit of both. It all comes down to how much energy you want to expend on a topic of conversation. If someone gets offended, you can apologize, maybe just let that one go, and move on to another topic. Or maybe it's worth debating over, there's no hard and fast rule.