The first interesting item in these verse is the simple phrase "that when the Lamanites found that their daughters had been missing…." While it is a very simple point, it is nevertheless one that should be made; the Lamanites were expecting that their daughters would be away on their own for some length of time. This reinforces the concept that they were participating in a known ritual at a known time. Their parents were concerned only when a certain time had passed. This also indicates that there was no direct supervision over the dancers, and this fact certainly led to the ability of Noah's priests to abduct them.
The next similarly small but important point is that the Lamanites immediately suspected Limhi's people. There are multiple reasons why this might have been so. The first possibility is that the traditional conception of Lamanites and Nephites is correct and the Limhites were suspect because they were the only other people around. While that idea is acceptable given the premise, it is not the operating premise of this commentary, nor consistent with the information we have from both archaeology and internal data in the Book of Mormon.
If we assume that there were other populations somewhere around (all subsumed under the rubric of "Lamanites") we may legitimately ask the question as to why the Limhites were so immediately suspect. Certainly the answer lies in the conflict just resolved between the two peoples. The Lamanites had attacked Lehi-Nephi, and while there was a tribute treaty in place, it would not be completely out of the question that some of those tributaries might attempt to retaliate by taking the Lamanite women. Thus the accusation is logical against the Limhites, but not because they were absolutely the only choice. They were the most logical choice, with motive and opportunity.
The last item that is of import in these two verses is the direct participation of the Lamanite king. Verse 7 places the king at the head of an army of destruction that gathered before Lehi-Nephi. In contrast, we do not specifically hear of the king in the army of conquest that created the treaty recently discussed. Why is this occasion more deserving of the presence of the Lamanite king than the previous military action against Noah?
There are likely compounding reasons for the king's participation. One would be the necessity to forcefully put down any attempt at rebellion by a tributary. While the army might create the beholding city/state, once a tributary to the king, the king could not allow for such blatant tweaking of the Lamanite king's power. Secondly, the dancers were probably (as has been noted) involved in a religious rite. Thus their abduction is not simply an affront against the Lamanites as a people, but against their god(s). This religious violation would also require retribution.
What would have played a smaller role in the retaliation was the anger over the loss of the daughters themselves. While modern societies would assume that anguish for a child would be a paramount emotion, this may not have been the case in the ancient world. Not only was life cheaper in many ways in the ancient world, but there is no indication that the king was personally related to any of the dancers. Without such kin bonds, there would be nothing in particular to tie his emotions to those who were abducted. Additionally, we must remember that those who were abducted were women, and we should remember that the social status of women in Israelite society was secondary, and that they were also probably marginal in terms of political/emotional importance in most of the Mesoamerican communities. It is very possible that in an ancient culture, the fact that those abducted were "only women" could have diminished the response, not heightened it.
Of course we may only guess at the motivations of the Lamanites when they marched against Limhi, but the best founded speculation would see the retaliation in more ancient terms as an action of political and religious significance more than simple parental love.