This proposed law, which looks like it’s probably going to pass, is part of a nationwide movement by conservative parents to to stop schools, especially elementary schools, from teaching about or discussing LGBTQ people.
DeSantis is on board the movement because it’s politically popular, and he knows it will fire up voters supporting him and his Republican allies in Florida.
It’s probably important to point out that the basis for conservative parents' complaints is fundamentally flawed. Their central argument, in Florida and around the nation, is that they have the right to discuss sex with their children on their time table and through the lens of their values. They have the right to demand schools not interfere with that parental process.
But gay and trans people exist, and we are no more about sex than cis/straight people are.
Straight people form couples, have girlfriends and boyfriends, get married, etc, everyday. And nobody hesitates to talk to young children, even very young children, about that.
By prohibiting discussion of gay people in classrooms, by saying it’s because children are too young to hear about sex, schools and politicians teach only one lesson:
Being gay is something to be ashamed of and hidden. Being gay is centrally about shameful sexual activity that children are too young to know about.
That’s why this movement is so toxic.