Why Christians eat pork though Deuteronomy 14-8 clearly prohibits swine?

"...Do ye not perceive, that whatsoever thing from without entereth into the man, it cannot defile him; Because it entereth not into his heart, but into the belly, and goeth out into the draught, purging all meats?...." This is a total contradiction to the science and common sense. We get most of the diseases through meals, water and air and all the things we eat changes as blood and nourished our entire body.

"...That which cometh out of the man, that defileth the man..." If this is correct, the milk come from mother's breast is also unclean. Is it correct?

"There is nothing unclean of itself. -- Romans 14:2" . This verse is not in The Bible. Any how it means "nothing unclean itself" - not to others.

Romans 14:2-8 (New International Version)2One man's faith allows him to eat everything, but another man, whose faith is weak, eats only vegetables.

because the New Testaments remove this prohibition;

And he saith unto them, Are ye so without understanding also? Do ye not perceive, that whatsoever thing from without entereth into the man, it cannot defile him; Because it entereth not into his heart, but into the belly, and goeth out into the draught, purging all meats? And he said, That which cometh out of the man, that defileth the man. -- Mark 7:18-20

Peter went up upon the housetop to pray about the sixth hour: And he became very hungry, and would have eaten: but while they made ready, he fell into a trance, And saw heaven opened, and a certain vessel descending upon him, as it had been a great sheet knit at the four corners, and let down to the earth: Wherein were all manner of four footed beasts of the earth, and wild beasts, and creeping things, and fowls of the air. And there came a voice to him, Rise, Peter; kill, and eat. -- Acts 10:9-13

There is nothing unclean of itself. -- Romans 14:2

Now the Spirit speaketh expressly, that in the latter times some shall depart from the faith, giving heed to seducing spirits, and doctrines of devils ... commanding to abstain from meats, which God hath created to be received with Thanksgiving of them which believe and know the truth. -- 1 Timothy 4:1-3