Plundering the Egyptians?

Every now and then I hear a christian leader defend their use of secular thinking (or crappy christian thinking) under the excuse of plundering the Egyptians. The reference is of course, to the Israelites taking the gold, silver and clothing of the Egyptians as they left during the Exodus. It is used as a metaphor for taking the 'best' of a culture and your surroundings, without fear of contamination. I think it's use like this comes from Wesley, (though it is there is Origin and Augustine relating to philosophy in particular), who used it based on his belief that God was the God of all truth, and so anything that was true and good in a culture could be used for God's glory.
Now, as a principle, it isn't so bad. But I wonder whether it works as a metaphor. The thing that bugs me is that well before this silver and gold was used as a freewill offering to build the tabernacle, the gold was melted down, made into a golden calf and pronounced to be 'the God who brought you out of Egypt'. Maybe it does work as a metaphor!
So for example, there are people in my church who subscribe heavily to the 'Babywise' parenting method, that says that your children are evil little sinners who need to be brought into line by imposing a routine on them. Some christians say, "oh well, we can still 'plunder the Egyptians' and take what is good out of this program, even though it's theology and use of the Bible is suspect." Which may be good and well for those who know that the God of Israel and of Jesus Christ has nothing to do with such monstrous excrement, but for those who don't, I wonder whether they hear "This is the God who brought you out of Egypt". This man made construct, justified by it's appeal to the true and living God, is plundering the egyptians to make a Golden calf, why should the church have anything to do with something that distorts God so heavily?
(As a side note, the little man is basically on a routine, but not because it is 'God's way' of raising children, but because it is what seems to be working for him and us at the moment).
I wonder whether quite a bit of 'plundering the Egyptians' falls into the same trap?