I wouldn't really call this a "roast" of the New Kids but more like a "homage" to it. I think the writers did a pretty good job of trying to mansplain why it was pre-pubescent and pubescent girls who liked the "Beantown boys" so much.
I must say I was pretty skeptical that the writers would handle the writing of this episode in a tasteful way and see the humor in it without being "mean" and "petty" but I was wrong. It was a well thought out episode and was tastefully written.