I have mixed – but mostly negative – feelings about all this.
Contrary to the news pointed by the original poster, I don't see them Father's day and Mother's day as excluding people. It's possible to have two fathers or two mothers and fit the bill, and if well done, it is a way to highlight that both parents play a role in raising kids.
My issues are twofold.
1. In the name of "openness", we tone down references to Christmas and Easter, which have become almost forbidden terms. And Christmas has stopped a long time ago being a commemoration of the birth of Jesus. And yet at the same time we have no issues promoting Valentines Day (Saint-Valentin in French, by the way) and Halloween, or endoctrinating our kids about Santa Claus. If we remove Jesus from schools because his holiness isn't proven (and I agree), we should certainly remove Santa Claus as he is proven to be a commercial creation.
2. As a person who is not an artist, to put it mildly, I have always despised those school moments where we were suddenly to express something thoughtful with a drawing. If you want me to express something decent, ask me to think or write about it, but don't ask me to draw about it! And even if you show me a nice drawing of a family, even one made by a professional, don't ask me to see any sign of love or thankfulness in it.