Ummm...Protestants do not claim the Law wasn't meant to be obeyed, only that we all fail to do so. If it wasn't meant to be obeyed, then it could be ignored.
Romans 7
"12 So then, the law is holy, and the commandment is holy, righteous and good. 13 Did that which is good, then, become death to me? By no means! But in order that sin might be recognized as sin, it produced death in me through what was good, so that through the commandment sin might become utterly sinful.
14 We know that the law is spiritual; but I am unspiritual, sold as a slave to sin. 15 I do not understand what I do. For what I want to do I do not do, but what I hate I do. 16 And if I do what I do not want to do, I agree that the law is good. 17 As it is, it is no longer I myself who do it, but it is sin living in me. 18 I know that nothing good lives in me, that is, in my sinful nature. For I have the desire to do what is good, but I cannot carry it out. 19 For what I do is not the good I want to do; no, the evil I do not want to do—this I keep on doing. 20 Now if I do what I do not want to do, it is no longer I who do it, but it is sin living in me that does it.
21 So I find this law at work: When I want to do good, evil is right there with me. 22 For in my inner being I delight in God's law; 23 but I see another law at work in the members of my body, waging war against the law of my mind and making me a prisoner of the law of sin at work within my members. 24 What a wretched man I am! Who will rescue me from this body of death?"
Here's a news flash: it didn't take chr*stianity to discover that no one's perfect.
Human frailty doesn't negate the obligation of Israel to obey Torah (and non-Jews to obey the Noachide Laws).