Mother’s day is to celebrate mothers.
Some “lesbian” females can be mothers. If so, they will celebrate as mothers, not because of their homosexuality.
Why do we have to take any specific celebration and then say it’s not inclusive enough because of this or that reason?
Not all women are mothers. So this day isn’t about them. Why is any of this so controversial?
But everyone has a mother, or had a mother at one time. Our church is supportive of grown women who never had children even though they wanted to, and they participate in the Mother's Day lunch. Several of our congregation's mothers also underwent the loss by death of growing or grown children, and they come to the lunch, also. We pray for one another in sorrows as well as joys.
As far as family observations go, basic human decency and tact—on every side, the mothers, the childless, the straights and the queers—creates inclusiveness among loved ones. If a family is already accepting or not accepting an LGBT member for whatever individual reason, the "gendered" holiday will be treated the same.
As for the public schools, why are they even involving themselves in what should be private family instruction or traditon? That goes quadruple for anything related to sexual behavior.