How could god allow this?

Gen 16:1 says, “Now Sarai Abram's wife bare him no children: and she had an handmaid, an Egyptian, whose name was Hagar.

16:2 And Sarai said unto Abram, Behold now, the LORD hath restrained me from bearing: I pray thee, go in unto my maid; it may be that I may obtain children by her. And Abram hearkened to the voice of Sarai.

16:3 And Sarai Abram's wife took Hagar her maid the Egyptian, after Abram had dwelt ten years in the land of Canaan, and gave her to her husband Abram to be his wife.

16:4 And he went in unto Hagar, and she conceived: and when she saw that she had conceived, her mistress was despised in her eyes.”  Maybe Abram and Sarai weren’t praying or something but what a cruel joke to give the man god had given a boatload of seed, a wife who could not conceive.  That is just in bad taste.