I don't think this is very complicated. When you say something in the context of an ongoing conversation, people are going to interpret you as saying something relevant to that conversation. I mean, why else would you be saying something?
You jumped in to object to talking about Brown as a "child". You said "The guy was 18 and 6 foot 4, and capable of robbery, he was hardly a child". Now, presumably you were paying attention and didn't think people were unaware that Brown was about that age, though maybe they didn't know that he was a bit taller than average? "Capable of robbery" is pretty useless, as descriptions go. It's hard to see what this post is trying to accomplish, if we're being charitable. I guess your position now is that you were just being pedantic for no good reason and were looking to have an argument over the definition of 'child' (specifically, whether it's appropriate to talk about people at an age where many have never had real jobs, are still in high school, live with their parents, and are listed as dependents on their parents' tax returns as 'children'). That's kind of a silly point to drop this sort of one-liner about, and if you really felt the need to make this point anyway you should have stopped to think about how it would look - a couple more sentences making clear that you're only wanting to be pedantic and aren't trying to justify his killing would have helped.
But then in a later post you go on and talk about how he wasn't an "upstanding citizen". And by now I don't think anyone's buying that you were just being pedantic earlier. That someone isn't an "upstanding citizen" means they're not a "child"? Clearly we've moved on to dancing around how, while maybe this is tragic and all, it's not nearly as tragic as it'd be if Brown weren't 6' 4".
