So far I don't see anyone but Paul saying to quit following the laws given in the OT. Some of the laws don't make sense now because we don't live in a desert, tribal culture. That makes it seem that they don't apply at all but Jesus followed them. He fulfilled all the requirements and told us to do the same and more. More?! But that's what he said, that he was out of time but his followers should be doing greater things than he did.
It's difficult to separate the things that were actually commanded from the things that were set up in the religion that just made it more difficult. Like Jesus not ceremonially washing his hands before he ate (I have to add ceremonially because thinking he just didn't wash his hands at all seems rather gross, but the ceremony was the part he objected to); was there a commandment in the OT for everyone to go through some ceremony like that? And the sabbath, he kept the sabbath obviously but he refused to do all the heartless religious soul-sapping parts that were expected by then. Healing and doing good on the sabbath, was that ever proscribed before?
The OT law was given to show what a life of love for YHWH looked like and a love for your neighbor (fellow man/woman). I can easily see how people could start "doing the law" instead of letting it be the guideline and proof it was set up to be.
Edit - Studying Paul and doing word studies show he wasn't "authorizing" such a radical rewriting of God's laws anyway.
Something else I always think of is, if someone now is given a wonderful revelation, we tell everyone what we were shown, does that suddenly mean that every thought we have and every word we speak from then on comes directly from YHWH? No. So why do we do that to Paul?