More unjust punishment

Gen12:15 says, “The princes also of Pharaoh saw her, and commended her before Pharaoh: and the woman was taken into Pharaoh's house.

12:16 And he entreated Abram well for her sake: and he had sheep, and oxen, and he asses, and menservants, and maidservants, and she asses, and camels.

12:17 And the LORD plagued Pharaoh and his house with great plagues because of Sarai Abram's wife.”  The Pharaoh didn’t know because Abram lied to him.  Shouldn’t the liar be punished?  The Pharaoh actually treated him really nice.