It's because we like rules we can follow and make others follow. It's easier than living by faith. And then there are all the folks who are the former talking like they have freedom and don't, making fun of the folks who really do. It's a mess.

I don't know if they are Christians. They may be Jewish. Christians would believe in Christ. I see more freedom in some areas. +5

I cannot explain why those who say they are Christians live under the Old Covenant, and yes, this would include the sabbath and tithing. Maybe in time someone who says they are, will give their explanation. Maybe they will read this and get an understanding to what Gods' word says. Also you can also give a witness to them to help them get insight to the truth of the matter. The Bible states that by means of Christs' blood that all Christians would no longer be under the Mosaic Law which was specifically given to the Nation of Israel. see Exodus 19:5,6; 24:3,8; 34:27; ; Deut 29:1,9: 6:1. Jeremiah 31:31,32. Luke 22:20-29 Hebrews 9:13-15. Col 2:14.

Both the Old (Mosaic) Covenant and the New Covenant apply to Jews only; . "I will make a new covenant with the house of Israel, and with the house of Judah:" — Jeremiah 31:29-31 . Jesus was a Jew and his message and mission was for Jews; Matthew 15:22 "And, behold, a woman of Canaan came [..] saying, Have mercy on me [..] for my daughter is vexed with a devil" . 15:23 "But he answered her not a word" [..] . 15:24 "But he answered [to his disciples] and said, I am not sent but unto the lost sheep of the house of Israel" .. And as Jesus himself later said about the law and the prophets - "I have not come to abolish them but to fulfill them. I tell you the truth, until heaven and earth disappear, not the smallest letter, not the least stroke of a pen, will by any means disappear from the Law until everything is accomplished” (Matthew 5:17-18). . In some cases Jesus actually gave stricter interpretations of the law than Moses did, concerning adultery for example. . I hope that your belief that there is a new covenant, that it it applies to you and that it means that you don't have to follow OT law, is a source of some comfort for you. But if it is then that is all that it is... it's not really backed up by the words of either God or Jesus.