The OT law also teaches you must make a sacrifice to cover your sins.
What kind of animals are you whackin and how often?
IF you are not doing this, then you are in violation of the OT law and on your way to hell.
The Israelites were given a number of laws that had the condition "when you enter the land..." while they were still wandering the wilderness for 40 years, so there is nothing wrong with not following a law that can't currently be followed. When the Israelites were exiled in Babylon, the condition for their return to the land was to return to obedience to the Torah, which contained commands in regard to temple practice that couldn't be followed because the temple had just been destroyed, so God honored their obedience to the commands that they were able to obey. In 2 Chronicles 30:15-20, Hezekiah prayed that God would pardon everyone who sets his heart to seek God even through that had not acted in accordance with the sanctuaries rules of cleanness and God heard him and healed the people. This was also taught to early Christians:
Didache 6:2 For if you are able to bear all the yoke of the Lord, you will be perfect; but if you are not able, what you are able that do.
So while there are illegitimate reasons for not following certain laws (James 2:1-11), there are also legitimate reasons for not follow them.
Actually you are anyway according to Galatians 5:4 but of course those following the OT law do not accept the New Testament.
All throughout the Bible, God wanted His people to repent and to return to obedience to the Mosaic Law, and even Christ began his ministry with that message, so it would be absurd to interpret Galatians 5:4 as Paul speaking against doing that and warning that we will be cut off from Christ if we follow Christ. In Psalms 119:29, he wanted God to be gracious to him by teaching him to obey the Mosaic Law, so that is what it means to be under grace, and it would again be absurd to think that he wanted God to be gracious to him by teaching him how to fall from grace.
You should be quicker to think that you've misunderstood the book of Galatians than to think that it makes perfect sense to interpret as teaching us to rebel against God's commands, and the bottom line is that we must obey God rather than man, so even if your interpretation of Galatians were correct, you should be quicker to disregard everything said in the book than to disregard anything that God has commanded. If it comes down to obeying what God has commanded or obeying Paul, then it should not be difficult to figure out which one has the higher authority and which one we should follow, though the reality is that Paul was a servant of God who never spoke against anyone obeying anything that He has commanded, so it doesn't need to come down to that.
I used to be against obeying the Mosaic Law, so I've seen how the NT can be interpreted as speaking against it, but I've tried interpreting Paul as though he meant what he said in Romans 7:22 that he delighted in obeying the Mosaic Law, so I've also seen how it can be interpreted as being in favor of obeying the Mosaic Law, and it makes far more sense to interpret God's word as being in favor of obeying God's word. In Psalms 1:1-2, blessed are those who delight in obeying the Torah of the Lord and who meditate on it day and night, and we can't believe in the truth of these words as Scripture while not allowing them to shape our view of the Mosaic Law.