If what you want to get across to Christians is to go against all Christ tells us about how we should live, that we should never try to follow Christ---surely you know better.
If you say that all the Hebrews went through when they were freed from slavery in Egypt means nothing, God was doing nothing with that, it is something no one who knows the most elementary things of God would say.
The law from the O.T. is a guide to Jesus Christ. The freeing of the Hebrews from the slavery in Egypt only has relevance for the Christians because it points to the freeing from sin and death by the Sacrifice of Jesus Christ. The Old Testament only has relevance in the measure it prophecies about Christ. The biggest revelation we have from God is in Jesus Christ and not in the O.T.
The law of the O.T. is not a purpose in itself, but only a mean to a purpose - Jesus Christ.
So, yes, to keep the law IS a nonsense.