1Yahweh spoke to Moses, saying, 2“Speak to Aaron, and to his sons, and to all the children of Israel, and say to them, ‘This is the thing which Yahweh has commanded: 3Whatever man there is of the house of Israel who kills a bull, or lamb, or goat in the camp, or who kills it outside the camp, 4and hasn’t brought it to the door of the Tent of Meeting to offer it as an offering to Yahweh before Yahweh’s tabernacle: blood shall be imputed to that man. He has shed blood. That man shall be cut off from among his people. 5This is to the end that the children of Israel may bring their sacrifices, which they sacrifice in the open field, that they may bring them to Yahweh, to the door of the Tent of Meeting, to the priest, and sacrifice them for sacrifices of peace offerings to Yahweh. 6The priest shall sprinkle the blood on Yahweh’s altar at the door of the Tent of Meeting, and burn the fat for a pleasant aroma to Yahweh. 7They shall no more sacrifice their sacrifices to the goat idols, after which they play the prostitute. This shall be a statute forever to them throughout their generations.’
8“You shall say to them, ‘Any man there is of the house of Israel, or of the strangers who live as foreigners among them, who offers a burnt offering or sacrifice, 9and doesn’t bring it to the door of the Tent of Meeting to sacrifice it to Yahweh, that man shall be cut off from his people.
10“‘Any man of the house of Israel, or of the strangers who live as foreigners among them, who eats any kind of blood, I will set my face against that soul who eats blood, and will cut him off from among his people. 11For the life of the flesh is in the blood. I have given it to you on the altar to make atonement for your souls; for it is the blood that makes atonement by reason of the life. 12Therefore I have said to the children of Israel, “No person among you may eat blood, nor may any stranger who lives as a foreigner among you eat blood.”
13“‘Whatever man there is of the children of Israel, or of the strangers who live as foreigners among them, who takes in hunting any animal or bird that may be eaten, he shall pour out its blood, and cover it with dust. 14For as to the life of all flesh, its blood is with its life. Therefore I said to the children of Israel, “You shall not eat the blood of any kind of flesh; for the life of all flesh is its blood. Whoever eats it shall be cut off.”
15“‘Every person that eats what dies of itself, or that which is torn by animals, whether he is native-born or a foreigner, shall wash his clothes, and bathe himself in water, and be unclean until the evening. Then he shall be clean. 16But if he doesn’t wash them, or bathe his flesh, then he shall bear his iniquity.’”
Deut 12:2 "Ye shall utterly destroy (חרם, ḥērem)" -Israel is supposed to be totally separate culture from those around them.
The passage here is much about the centralization of worship in Deuteronomy, and as such a very important topic in academic discussion in Old Testament scholarship for the last 200 years. Without going here into any of the complications and various opinions expressed, according to Deuteronomy’s vision, Israel is to gather together in one place for worship three times a year, and sacrifice their offerings only in that place. In a broader context, this is to happen when the nation has settled in the land and is at peace, and such travelling is possible in practice (Deuteronomy 12:10-11). In other circumstances, one may sacrifice locally (cf. Exodus 20:22-24; cf. Deuteronomy 27; Joshua 8:30-35; note however that, according to Leviticus 17:1-9, during the time in the wilderness, all sacrifices had to be brought to the tent of meeting, the Israelite sanctuary at the time). In a yet broader context, the concern of Deuteronomy, and the Pentateuch and Old Testament as a whole is that the Israelites worship only their God Yahweh. From another angle, as part of the settlement and striving towards purity in life and worship, the indigenous nations and their worship practices are to be eradicated so that no trace is left to lead Israel astray.
In modern thinking, the command in Deuteronomy actually amounts to genocide and is therefore problematic, particularly for those who take a high view of Scripture, and raises the question of theodicy, or the justification of God’s actions. But, if one reads the book of Revelation or even the New Testament as a whole, the apparent concept of damnation to unbelievers is at least arguably in line with the concept of killings of non-Yahwists in the Israelite conquest tradition. The issue at hand here is also perhaps mitigated by the fact that the Israelites did not manage to drive out or kill many of the native inhabitants, and by the fact that the conquest and settlement are to be considered as a one-time non-repeatable set of events.
All this said, as the nations were left in the land, as the Bible describes, the Israelites started to follow their practices (see the book of Judges in particular). These points considered, for Christians the passage can be read to promote fleeing away from idolatry and from any practices that are contrary to good Christian ethical principles, in line with New Testament material (cf. 1 Corinthians 10:14). The New Testament also seems to ask Christians to think of whom they associate with (1 Corinthians 15:33), and yet, this does not mean that one cannot associate with those who are not Christian (1 Corinthians 5:9-11). Jesus himself associated with all, and the Pharisees who criticised him for that are described as hypocrites by the New Testament (see e.g. Matthew 9:9-13, 22:18, note also that Paul in 1 Corinthians 15:33 might be quoting a popular proverb of the time). So, great wisdom and humility is required of Christians in following God with joy and ethical verve, while at the same time refraining from dubious practices without becoming haughty, condescending, or even violent towards others.