I wrote this intoxicated. Nonetheless, I think I touched on something of value, here. Sorry if it's a little hard to follow.
Different people take all sorts of different stimuli differently. Some people sleep in socks. Others express violent disgust at the thought. And still others do it sometimes, but not all the time. Our reactions to unexpected noises vary too, for example. The numerous genres of music, food, film, all manner of different choices of stimuli a person experiences during the day, all of these will be understood, experienced, and interpreted differently.
This fact, that everybody experiences reality in a fundamentally different way, has led humans to develop hugely different methods of communication. For good or for ill, these communication developments have allowed some humans the ability to transmit experiences through stimuli that humans are bad at guarding against. These advertisements are designed to target portions of human behavior that are caused by the body and mind in conjunction, rather than just the moment-to-moment needs of the conscious mind. This method is used because it is extremely effective, in one way or another, at convincing large numbers of humans to pay for specific things within a short time of one another.
Doing this effectively is key to advertising. It's also an incredibly difficult, and at-times unpredictable field. Enormous quantities of time and money go into finding ways to target specific portions of the population as effectively as possible. This demographic breakdown must necessarily involve race, gender, interests, hobbies, all this and far, far more. And since advertising receives essentially endless money from every industry right now, it's extremely effective. Effective enough, in fact, to convince people that they want things they don't want. Cars. Clothing. Houses. Smart refrigerators. All manner of gadget, clothing brand, car, every consumer good and service imaginable, all these things have a market, and the companies paying these advertisers know that all they must do is awaken these latent markets that are just waiting to be released. In a way, they're actually designed to awaken wants and ideas that the person didn't know they had.
Gender is a social construct. We know this fairly well, I think. Which makes the whole "transgender" thing a bit philosophically messy, doesn't it? Something in those of us who are non-cis is causing us to know that we're non-cis. But what? It can't be a biological thing, because it can't be tested for. Something in us is naturally drawn to the other* gender, though. How to resolve this philosophical issue? I know I am effectively genderless, but I can't define in any meaningful way what it means to be either gender at all without resorting to cultural archetypes.
I posit this: Our culture is so steeped in gendered advertising that it is quite literally shaping how we treat gender as a concept. What is a woman? A woman is a human who buys objects** advertised to women. What is a man? A man is a human who buys objects advertised to men.
The corporations and governments that can afford to advertise in this manner all have varying motivations for doing so, but nonetheless they are all making an effort to enforce a bi-gender status quo - it permeates everything, everywhere. Gender is the word we use to describe the parts of us that are activated when experiencing certain stimuli, and those stimuli just so happen to be extremely aggressively overwhelmingly used to sell you shit - be it a product, a service, or an idea. This heteronormativity, this unjust but somehow universal assumption that gender is an incredibly strict distinction between one and the other, is a tool by which people who want your capital - either in the form of your money or your body and time - intend to take it from you.
There will be people who read this and think I'm trying to convince you that you can't be trans because gender is a lie. There will also be some who read it and think I'm trying to convince you that you have to give up your cisdom because it is somehow "unnatural" under this way of thinking. To both: No, and you're horribly missing the point. These parts of you are very real. But you weren't allowed to discover them for yourself. Whether cis or trans, you had a core part of your identity - that is, your gender identity - taken from you and unshaped and reshaped and destroyed and rebuilt all throughout your youth. This vital stage of development did not and could not occur naturally, because it was experiencing intense overstimulation from a thousand sources at once. And it is only now, as a more knowledgeable person, that you can comprehend its true nature within yourself to any degree at all. Most people will probably never fully develop this part of our identities, the damage is too extensive.
*Or no gender at all, or some form of animal, I use the word "other" here incredibly inclusively. I just couldn't find a good way to phrase that in-line.
**It should be pretty clear by now that I'm not using "object" here to strictly mean physical objects specifically, right?