Biblical Blood

I am appalled at all of the blood in the Koran, Jewish Bible and Christian Bible. They all contain the Pentateuch which has portions that are very specific about blood and the parts of slaughtered animal sacrifices. Put the blood here, but not there; offer up these animal parts, but not these; and so on and so on. In some places God mentions how he likes the scent of fresh blood and burning flesh. Was all of this obsession with blood and butchering really necessary?
Here is a sample of text from Exodus 29. What did these animals ever do to God? Put blood on your earlobes, right thumb and right big toe??? Ridiculous.

Exodus 29

¹⁵ “Take one of the rams, and Aaron and his sons shall lay their hands on its head. ¹⁶ Slaughter it and take the blood and sprinkle it against the altar on all sides. ¹⁷Cut the ram into pieces and wash the inner parts and the legs, putting them with the head and the other pieces. ¹⁸ Then burn the entire ram on the altar. It is a burnt offering to the LORD, a pleasing aroma, an offering made to the LORD by fire.

 ¹⁹ “Take the other ram, and Aaron and his sons shall lay their hands on its head. ²⁰Slaughter it, take some of its blood and put it on the lobes of the right ears of Aaron and his sons, on the thumbs of their right hands, and on the big toes of their right feet. Then sprinkle blood against the altar on all sides. ²¹ And take some of the blood on the altar and some of the anointing oil and sprinkle it on Aaron and his garments and on his sons and their garments. Then he and his sons and their garments will be consecrated.

 ²² “Take from this ram the fat, the fat tail, the fat around the inner parts, the covering of the liver, both kidneys with the fat on them, and the right thigh. (This is the ram for the ordination.) ²³ From the basket of bread made without yeast, which is before the LORD, take a loaf, and a cake made with oil, and a wafer. ²⁴ Put all these in the hands of Aaron and his sons and wave them before the LORD as a wave offering. ²⁵ Then take them from their hands and burn them on the altar along with the burnt offering for a pleasing aroma to the LORD, an offering made to the LORD by fire.

⁴⁰ With the first lamb offer a tenth of an ephah of fine flour mixed with a quarter of a hin of oil from pressed olives, and a quarter of a hin of wine as a drink offering. ⁴¹Sacrifice the other lamb at twilight with the same grain offering and its drink offering as in the morning—a pleasing aroma, an offering made to the LORD by fire.