Baby’s bald spot makes me feel like others see me as a horrible mother

My baby is 4 months old. She was born with a medium amount of hair.

Shes got a significant amount of balding on the back and sides of her head. Theres a band about an inch and a half thick thats BALD.

Shes only in her crib for bedtime.

Other than that Im holding her. Or shes rotating in a bouncer, swing, play mat.

Someone commented “if she wasn’t left laying so much she wouldnt be balding”.

Her pediatrician says thats not true. And her head shape is gorgeous (esp for a vaginal delivery mind ya!) which means obviously shes not laid down or left too much

But I cringe inside that anytime anyone sees her they’re assuming I just leave her laying!!!

Advice? Help? Encouragement?