It's more a matter of community than of trying to get one over on God. The identity is "We are the people who follow these rules," and in particular, "others are those who don't". Compare it to Western revulsion at people who eat insects or dogs, even though they're as nutritious and safe as anything we eat.
The rules come from God because Jews consider themselves a chosen people. They don't particularly want you to follow those rules or concern yourself with the mechanics of them, because they're not about you. The fact that it doesn't make sense is perfectly fine.
Interpreting those rules in a modern context is every bit as arcane and arbitrary as the rules were in the first place. The important part is that they come to a conclusion and follow them together. That cements the society as a group.
It doesn't really matter what God thinks, either. If God had a contrary opinion, He'd say so. There is, for that matter, a famous story about rabbis coming to a conclusion that God explicitly sends messages against, but is pleased that they have used their reason.
The Jews put a lot more weight on community and a lot less on trying to please their deity by following the rules. It just so happens that the rules really are both things.
