It wasn't created unclean:
Gen 9:3 Every moving thing that liveth shall be meat for you; even as the green herb have I given you all things.
Gen 7:2 Of every clean beast thou shalt take to thee by sevens, the male and his female: and of beasts that are not clean by two, the male and his female.
YHWH had a purpose in preserving more clean beasts than unclean for use after the flood. Certain flesh became food as most vegetation was destroyed. Notice that Noah knew there was a distinction between clean and unclean animals long before the dietary law was codified at Mt. Sinai and long before a Jew ever existed. This proves that the clean food laws commanded in Leviticus 11 and Deuteronomy 14 were not given only to the Jews. They were given to all men at least from Noah's day forward.
After the universal flood, YHWH said in
Gen 9:3-
4, "Every moving thing that lives shall be meat for you; even as the green herb have I given you all things. But flesh with the life thereof, which is the blood thereof, shall ye not eat." He was speaking to Noah and his sons (vs. 1). Noah knew the difference between clean and unclean animals. Therefore, when YHWH said, "Every moving thing," Noah knew that He meant every moving thing that was clean to eat. YHWH spoke similar words to Adam when He said, "every herb" and "every tree," shall be food for you (
Gen 1:29). Adam obviously knew that YHWH meant every herb or tree that was edible, for many plants are poisonous to man. He also knew "every tree" did not include the tree of the knowledge of good and evil.
In
Gen 8:21, YHWH said, " . . .neither will I again smite any more every thing living as I have done." Are we to understand this literally? Did YHWH smite those in the ark or aquatic life? No. Therefore, this verse needs to be qualified by understanding it to mean, "every thing living on the ground" as is revealed in
Gen 7:22; " And every living substance was destroyed which was upon the face of the ground, both man, and cattle, and the creeping things, and the fowl of the heaven; and they were destroyed from the earth: and Noah only remained alive, and they that were with him in the ark."
Based on these examples, Genesis 9:3-4 should be understood to mean, "Every moving thing that lives and is clean shall be meat for you; even as the green herb have I given you all things that are clean. But flesh with the life thereof, which is the blood thereof, shall you not eat."
Had Noah eaten one of the only two pigs, pigs would have become extinct.