I think Atta's point was that if someone does a live streaming webcam, if people miss it, they've missed it.
If you record it and edit it into a vid, you can sell it to anyone who's interested, who can then watch it at anytime they're available, and also watch it as often as they like. So you might have a larger market.
As far as assuming that you meant it would be of you, when you said "I" am going to set up a webcam, would you buy it; it would be a logical assumption that you would be the subject. If it will be of someone else, that's fine, but you didn't say that. And most people who come on here to talk about webcams, or vids (unless they specify that it will be of someone else) are talking about filming themselves.
Just an assumption; no harm, no foul. But you probably didn't need to say he was stupid for assuming that.
Unless there's a language mis-interpretation at work here ......