You apparently have not met many 6 year olds.
Have you? Why are you hanging around 6 year olds?
But yes, of course kids are impressionable. But a male teacher saying they have a husband simply tells the children that some men are married to other men. It's not "hyping it up", what kind of nonsense is that? It's simply a reality of the world we live in, and it's true whether bigots like it or not. Children need to understand the reality of the world they live in.
What was your sexuality at 6? I don't even think I consciously had one, who thinks about stuff like that at that age?
But as you get older and start feeling attracted to people then if that happens to be people of the same sex I'd suggest it's healthier to be living in a world where you're accepted rather than one where society tells you it's shameful and even acting on those feelings is illegal. No-one chooses which sex they're attracted to, I didn't "choose" to be heterosexual.
As much as you may misrepresent people, no-one here is suggesting the kids should be groomed. Simply that they should be accepted. I shudder to think how you would react if you have children and one of them turned out to be gay.