Can't the same argument be raise for Christianity? I'm sure at the time of Jesus he saw himself as rectifying Jewish practice (and of course there are the passages where he says that the old laws are still in force), but pretty quickly Christianity was modified and sold to gentiles (thanks to Paul, who never met Jesus and wrote 13* of the 27 books of the New Testament) and the Mosaic laws were mostly set aside.
The whole idea of "fulfillment theology" is that Jesus fulfilled the old covenant and established a new law. That is why Christians eat pork and so on.
* everyone agrees that three of those 13 weren't actually written by Paul, and three more are in various degrees of doubt