Did mohammad really like to see slave girls FREED?

bukhari vol. 3 book 47 page 765 al- harith told mohammad that she had manumitted a salve girl without taking the permission of the prophet of allah. ''on the day when it was her turn to be with the prophet, she said, '' do you know, ''o'' allah's apostle, that i have manumitted my slave girl? he said, ''have you really''? she replied in the affirmative. he said, ''you would have gotten more reward if you had given her to one of your maternal uncles. so did mohammad like the freeing of slave girls?