Why do christians persecute s- theological New Testament answers please.?

If, as Paul argues (against Jesus's specific teaching in sermon on mount) that the mosaic law has ped and we are free from "kosherdom" why pick a few of the mosaic laws to keep- in the OT god hates people eating oysters and bacon and inside toilets as well as gays, but we've accepted some but not others, why? - why not just the ten commandments with the emphasis on loving each other and god?