No, she doesn’t have a point. She’s lost all sympathy, respect, and logic once her argument was that Mashiro being brought up poor and “raised in an abnormal environment” is disqualifying.
The comment you pointed was written before this chapter and if you had any of this feelings toward her before that, that's not a good sign.
That's said, i'm pretty much done with the mom yeah. She had one chance here to redempt herself, even so sligthly, but decide to throw it out of the window cause "bla bla no parents, lesbian brothel". Imagine trying your best to get your life together after a hard life and someone just come and say "you're a bad influence for my kid" despite said kid being the scum of the earth even before meeting her.