(6)A parent’s affirmation of the child’s gender identity because it is in the best interest of the child to affirm their gender identity.
https://leginfo.legislature.ca.gov/faces/billTextClient.xhtm...
The subsection 6 that you quoted is under the section:
3011. (a) In making a determination of the best interests of the child in a proceeding described in Section 3021, the court shall, among any other factors it finds relevant and consistent with Section 3020, consider all of the following
For example, another subsection is
(3) The nature and amount of contact with both parents, except as provided in Section 3046
This has absolutely nothing to do with falling under child abuse.