He came from a dysfunctional home.I think a lot of people don't want to admit that Spock is a messed up person. He was messed up in TOS and he's messed up in Discovery. He probably wanted to pursue Kholinar to straighten himself out and to actually become what he thought he wanted to be.
Also no 21st century social worker with any wisdom would place young Michael Burnham in Sarek's and Amanda's care. What is one of the first things they do when they get her, put that nasty Vulcan wig on her head, denying her human ethnicity, its like bleaching the skin of a black child in your foster care to make her fit in with the white kids in the village.