when Jesus came and died and resurrected, he replaced the old covenant/testament with the new covenant/testament..in the first (old testament) people were under the law (ten commandments/golden rule/Jewish laws, etc) while we, the Christians, are under the new (testament/covenant).... we are under grace...we are "saved through faith not works lest any man should boast".
This was a radical departure from the old which required people to keep up extremely high standards of morality and obey many laws to get to heaven.
Unlike all the religions of the world (who have some version of the good go to heaven (or a similar place) and the bad go to hell (or a similar place)., this says bad people (from an earthly standpoint) can be in heaven and good ones in hell, (he says there will be thieves, murderer, homosexual, etc in heaven in the new testamen)t. It is a matter of our faith in the finished work of Christ...not our works..faith not works.
It is not that Jesus/God wants us to live immoral lives..far from it but He wanted us to see how far from being good we really were by giving us the 10 commandments..even for those who kept them like the pharasees, he pointed out how all their righteous was as filthy rags and called them whitewashed tombs with dead men's bones inside (appearing good outwardly but inwardly full of bitterness, unforgiveness, judging others, and without love in their hearts)
..God knew that man was essentially incapable of not sinning..yes some would be better than others but all fell far short of the mark of a Holy God which was perfection for "all have sinned and fallen short of the glory of God and the whole world stands hushed and guilty before him"
He hoped we would act out of love and gratitude in trying to obey His law with his supernatural help as we relied on Him... instead of out of obligation and fear..out of gratititude for his free gift to us bought at such a high price to Jesus and God the father.
A harsh father can enforce rigid obedience but it will cause resentments and not flow from the heart and may not be lasting when one is not in the father's presence but might cause the child to want to rebel, on the other hand, a kind and loving father who we are greatful to and don't want to dissapoint will engender us to try harder and do so out of love and from an intrinsic place whether in his presence or not as we have assimilated His values out of love, gratitiude, and respect. He gave us free will to see what we would do.
As far as the verses you have posted, the new testament specifically said we are free to eat whatever we choose now (but it suggests if we are with someone who believes eating a particular thing is a sin that we are wise and respectful to not eat the food when we are with him).
Many of the old laws are still good (keeping the 10 commandments and using the golden rule) but we are never to use this as a basis in being acceptable to God as only through the blood are we ever acceptable..both before and after salvation.
It is interesting, though, that new information on foods show that many of these old Jewish laws do make sense from a health standpoint. Shellfish are bottom dwelling and hence absorb more pollutants, fat it is said is not a healthy meat and is high in fat, etc.
These laws you quote apply to the Jewish people, not to Christians.