But that's not what " sex is a spectrum" means. It doesn't mean there is no dimorphic sex, that would be an absurd point of view. It means that there are genetic differences in sexual characteristics of members of the same sex.
As in, some men have more testosterone than others. It's obviously a spectrum, you seem smart. Use your head. That seems pretty pragmatic.
Your height analogy is perfect. There are not two pillars, you just said " average female height" and " average male height," that doesn't mean that all females are the same height and all males are the same height. It is a continuous value, a spectrum, which we place categories over. E.g. " average female height" is just a categorical description of a continuous value -- a height between a certain range. They fit into the range so they are in the categories. I challenge you to think of any categorical data that does not fit that context... Because there isn't any. That IS what categorical data is, because everything is continuous.
The idea of defined categories, especially when it comes to biology and evolution, is a socially constructed myth used to coopt these views with creationism.
In other words, you can't believe that we evolved from asexual single-celled organisms and hermaphroditic organisms if you believe God made man and woman in his image and put them in a garden together.
Not to say you are creationist, just that this idea being established is counter to all of the evidence (sexual evolution, homo evolution). We are not a clean, organized plate of vegetables. We are a clumsy soup made from the ingredients at the bottom of the fridge. One only needs to look at the known taxonomy of modern humans to realize how complex our genetic lineage and evolution via natural selection actually is.
While height is not necessarily a secondary sex characteristics, there are an array of secondary sexual characteristics which very between male, female, and intersex people.
You can literally look at gonads in every stage of development where they turn from ovaries and a clitoris into testicles and s penis. The most substantial difference is simply androgen. That is what caused the changes from female to male. That's why you have nipples that don't do anything.
We are talking about genes here, one gene difference can completely alter a person entirely. We have over 22,000 of them. It's just goofy to try and put some human organization over it and argue against it so fervently when it collides with that organization. I just don't understand it.
