Why is it that people are so stuck on there being just 'female' and 'male'?

Sometimes, predictability is just a bit easier to face. And, when they see someone's literal face is just a tad unordinary, they don't know what to categorize this person, as.

Some people have a hard time understanding things if its not them feeling that way. People are afraid of change, therefore they do not like thinking about the possibility of different or there being more than two genders.

People can often hold a grudge about there being more than two genders, maybe because they just aren't used to it. But the truth is that there are many genders and only you can decide your gender, no matter what it is. Everyone identifies differently and whatever you choose to identify as is completely fine and nobody can change your identity but you.

Gender roles are often seen as bery crucial in society (I personally think they don't have to be...). For many people, the way it has always been is the way it always has to be, hence they get confused and don't like the idea of there being more than just two 'boxes' for people to be out into, but rather a wonderful spectrum that people can move along. ... is one explanation. Gender roles are certainly a large factor, I would say, but there are many reasons.

It's a mixture of refusal to change as well as the idea that having more than two genders exist is illogical. If you connect gender with genitals, then you probably don't want to believe there are more genders than sexes (though, if we count intersex, there are technically 3 sexes, so go figure). Some people are resistant to letting go of this idea because it makes sense to them and seems logical; they don't find logic in any other ideas but their own. They don't want to accept that there are more genders because it doesn't fit their logic. People don't always change their minds and beliefs very easily; we're a very skeptical and stubborn species.

Many people are stuck in the rut of just seeing female and male as genders because that's what was the 'norm' in society in the past, it has only recently become more acceptable to be gender neutral etc. People often feel ill informed about LGBT type issues and therefore just shy away from them

for most of history, until recent years, it's only been acceptable to identify as either "male" or "female" so people coming up with words to describe how they feel (like agender, genderfluid, etc.) can make some people uncomfortable. Its not that these identities never existed before, we just didnt have a word for them because people who felt that way were discriminated against and oppressed

I don't know I gave up that ship long ago when I transitioned from one to the other physically. Ther eis a story in Native American cultures that we are all two spirited but the ones that are transgender are dubbed twop spirits as they experience both and accept that both are of equal value to who they are now. Getting hung up about something like gender is all sterotypes., but even those change with time. Gender is ambivalous word that often makes people feel comfortable that don't understand people of no gender, non binary or other varuiants from the 2 they knew being male and female.

People in general have a tendency to put labels in almost everything, and are normally weirded out when you go against or refuse to choose one of those labels. Gender identity is interpreted differently by everyone and it's supposed to be a personal experience for each individual finding out what their identity is. Just because people say you have to be one or the other it doesn't mean you have to fit yourself in a box to be accepted by others. The key is surrounding yourself with people who understand gender identity is a personal thing and that it's not limited to a 'female' or 'male' label

A lot of people were raised to believe that. It's hard to let go of something you've been taught your whole life. Others have a religious outlook. I find that a lot of people like to twist the Bible into "God hates you for this blah blah blah..". Times are different now and a lot of people have a hard time accepting that and adjusting their views. Either way, as long as you know who you are and you're happy with yourself, it doesn't matter what other people think. Some people are just uneducated. These kinds of things are new for a lot of people and new can be scary, so people would rather disregard the idea of something new than actually learn about it.