I've done it in spoken language since long before I heard of, yet alone used, the internet.

I rarely do it, "to dull the edges of an opinion". Instead, I do it to provide explicit context (e.g. this my opinion or my observation, similar to the way people will use 'IANAL' in discussion of a legal matter) and to let people know that I genuinely think I'm missing the point. The only way someone might be able to help fill in what I've missed is to explain what I see from my perspective. While most of the time, my perspective turns out to be pretty close to the mark, there have been times when I was really, really off, and someone was able to help provide the context necessary for comprehension.

In this particular case, I actually thought exactly the same thing as the original commentor and am glad to know that I'm not alone in my impression and subsequent confusion that "I think I'm missing the point"!