What age should kids learn about different sexual orientations?

[unpredictablemum]

I’ve been categorised as a closed minded parent for saying a 4 year old is too young to understand and that they might be confused by it, I’m now wondering if I am in the wrong? And most importantly to clarify I have absolutely nothing against people with different sexual orientations.
Back story is I was incorrectly told that the new superman is bisexual (it's actually a new character, superman's son) and as my son loves superhero's I expressed that my son might be confused if his favourite superhero started kissing men all of a sudden, is that not a fair comment 🤷‍♀️

On your 'nature and science' premise, as another example, let's talk about food.

Nature and science tell us that food is required for survival. Therefore, according to your line of reasoning, food is intended for survival, the purpose of food is survival, that's what food is for.

So I take it you never eat unnecessary food for pleasure? That you shun people who are overweight (well, you probably don't know any), or who enjoy food for pleasure's sake? You shield your child from knowledge of their existence, including through film and TV? Knowing they exist would cause confusion for your child, wouldn't it?

If not why not? Those practices and people are unnatural, surely? That is the default teaching to any child, right?

science and nature intended for male and female

Science and nature doesn't "intend" anything, they aren't sentient. I am unsure you understand the principles of evolution and advantageous mutations. There are plenty of things in nature that go against what we assume to be the norm for humans. Nature has no intent.

Talk of intention implies some God who set nature and science up to work a certain way to give certain desired outcomes.