Working moms being fired and crying discrimination

Anyone understand why working moms get so mad when they are fired after coming back from maternity leave and subsequently perform subpar at their work? I genuinely don't understand the logic. There are moms who vent about how poorly they are doing when they return to their job from maternity leave, commiserate about having "mommy brain", talk about how they want to cut out of work early because "my kids come first", and then are flabbergasted that they are being let go or fired. I don't understand how you can feign surprise and indignation, or threaten to sue the company for wrongful termination or discrimination, when you're openly admitting how badly you're doing at your job.

I understand there are some cases of discrimination, but when you demand to work from home, leave/arrive early every day, take days off because you kid is sick, and perform worse at your job due to "medical conditions" that mysteriously don't have the necessary medical documentation that could grant reasonable accommodations, what do you expect a business to do?