Some possible reasons to mention it:
The child's behavior was unusual or difficult, and frustrated the babysitter, contributing to the urge to murder the child;Reporters are so used to supplying reasons to pity the criminal of color, it just pops right out of their keyboard.the child required a more specialized caregiver that the unmarried parents did not or could not afford to provide.
Thank you for that angle; hadn’t thought of it. Nice try from the reporter, but won’t work with me. The woman said she wanted to get back at the dad, so it sounds more related to an unstable adult relationship than an unstable toddler.