Leviticus is dedicated primarily to instructing us in the various sacrifices that are brought in the Tabernacle and, later on, in the Temple, as well as other instructions pertaining to the work of the priests and the Levites.
When seen from this perspective, the rules of purity and impurity contained in this portion enable us to deepen our understanding of the overwhelming power of life and the overarching value that the Bible ascribes to it. Life is from God. Life is pure.
There is no way that the Children of Israel knew as they stood on the banks of the Red Sea, what effect this miracle would have on the surrounding nations. And, of course, in ancient times, news would not travel that fast in any case – it would be months before news reached Moab, Philistia, and Canaan.