No, I wouldn't. Their fingerprints, like their fibers, would be strange if absent from their own house. Intruder fingerprints would be more surprising, since most intruders wear gloves.
The fingerprints prove Patsy and Burke handled the table ware. The lack of other prints suggests they were the only ones to handle it. I suppose you could assume a gloved Intruder left no fingerprints, but someone that careful, in my opinion, isn't going to risk taking extra time to feed an abducted child pineapple. Besides, you have to assume something for which you have no proof -- that there was, indeed, an Intruder and that Intruder wore gloves. Why would someone careful enough to wear gloves be careless enough to risk getting caught feeding JonBenet pineapple?