How are you defining normal? on average 10% of people are left handed, does this mean that they are abnormal? Or does it mean that there are variations of humans and not one "Normal" human?
There are 9 billion people in the world, no two are exactly the same, which one is the normal one that we are all supposed to be like?
Using eyes as an example, there's a whole spectrum of abilities to see. Why do we need to define any one as "normal" and say that everyone else is "abnormal", why does that matter? Can't they simply be different? I've read that more people need vision correction than do not, does this mean that normal is not being able to see 20/20? In this example, I would define 20/20 as ideal or the target, not normal. What about eye color, which one is normal? Blue, brown? There are so many variations.
Normal is a concept. We simply choose to define something as normal if the majority fit into that category. There isn't really a normal.
The problem is that so many use that concept to be hurtful to others for no reason.
I don't care if one states that a trans female isn't a biological female, it's technically true. But to say that there is something wrong with the person, which "Abnormal" asserts, isn't necessary and in some context is bigoted. Why can't we simply accept that people are different and just agree that everyone is pretty much seeking the same thing, a happy life filled with love and acceptance.
My opinion is that many people are mean for no reason, and I just don't understand the need. We need to get past the stupid arguments that many on the right are making in their war on anyone who isn't exactly like them and focus on how we can make the world better for everyone.
Then there's also evolution. However slow, we are changing and evolving, so if something were to change through evolution, which is normal, the old version or the new version?
I actually believe that in a functioning society sometimes it is true what you're saying is technically true, but you shouldn't say it because it just is mean and unnecessary. But I will not say that these things can never be said, rather that the context of them being said matters and should be considered.
There's a big difference in saying: "trans females are not biological females" vs saying "they are just freaks and abominations".