The concept of kindness and selflessness is foreign to her
Come on, now. She is definitely always nagging them about getting a job but she knows very well that her kids have good traits. It was even at the center of a chapter showing the interaction between her and Souta's mother, it's not like she would kick then out at a moment's notice
She's nagging because, really, someone has to do it at some point, as a responsable parent. Having a job is the criterion to independence and stability she knows and she wishes it to her children both. But, that doesn't prevent her from accepting their lifestyle while it lasts.
There are lots of chapters where you see her doing house chores, while the siblings are at home and she just lets them be. Yeah, she could just say nothing, but that definitely wouldn't be any better parenting