There may have been a racial element to this, but from what I read, my sense is that this he was a self-hating incel who frequented massage parlors. He was heavily involved in his evangelical church, which is probably where the self hatred came from. Also, from social media posts, he bought into the alt-right anti China narrative espoused by our former Prez. A true plethora of potential motivations here.
In summary, this kid is ***** up.