Idk, for me fundamentally treating others as you’d like to be treated is about the social contract of tolerance - which is about not bothering anyone for their innate characteristics, to me if you follow the line of thought then “bother” can be defined as disruption and interference on top of outright obvious discrimination, and that includes emitting uncontrolled amounts of disruptive smells on unconsenting unsuspecting others.

It sounds like you are not, in fact, constructing "don't be horrible to people" as an imperative following from privacy, after all. Privacy is fundamentally about ensuring that other people cannot know what I'm doing, even if they want to. What we are talking about is ensuring that other people do not sense what I am doing because they may not want to. A violation of the former case harms me, but a violation of the latter case harms them. You're right to pick up on the consent of the stranger looking over my shoulder; the consent of the person sensing the impact is irrelevant in the case of privacy, but it is everything in the case of "don't bother other people." So let's come back to your analogy:

Why do you want random strangers to know what you ate? Hence the analogy, it’s the same question as why would you want others to know what you’re watching by blasting video on speaker on the bus?

I don't care if random strangers know what I ate. And as a privacy matter, that's the end of it. Privacy concerns don't exist if the person whose information it is consents to its release. I may care if they know what I'm listening to, because I think they'd be more likely to judge me for what I'm listening to. But if I agree to them finding that out, it's not a privacy concern at all. To extend the privacy argument: what business is it of yours why I want other people to know what I'm listening to? That's not what you're really concerned by. Really, you're concerned with me annoying random strangers. And my consent to annoying strangers is irrelevant; it's them who are being annoyed, they who must consent.

The reason I interpret what you're saying as discriminatory is because, as I already referred to, there are situations where it is not practical to keep your cooking smells hermetically sealed inside your own dwelling. Steaming up the windows is not a matter of how much garlic you're cooking, but how much water vapour is getting emitted from what you're cooking and how well ventilated the kitchen is - and any ventilation to let the humid air out lets out the smell of what you're cooking as well.

I don't disagree that there is a general principle that we shouldn't cause other people to smell stuff, but this principle is incompatible with other principles, such as keeping a comfortable level of humidity and eating where it's convenient (such as in public). The principle of don't-make-people-smell-stuff should rightly be considered to be very far down the list of principles' priorities when deciding which principle wins out, because causing someone to smell garlic is just not a big deal. It's not a foul smell (like fart gas) so it doesn't cause a big impact. In contrast, having to bottle up humid cooking air inside your home makes it uncomfortable and is a bigger impact. All of these principles should also be tempered by a fundamental societal determination of how reasonable activities are: cooking is something that basically everyone does, and garlic is an ingredient that basically everyone uses. In contrast, running a home chemistry set and synthesising fart gas is not something that basically everyone does; you could pick a different chemical to synthesise and get a similar enjoyment or, if you really want to synthesise fart gas, you can jump through some hoops to make sure the smell doesn't escape.

So let's stack it up:

• cooking with pungent ingredients like garlic is normal, reasonable, everyday activity
• it's not practical or comfortable to keep the smell inside
• the impact on others is minimal or even positive (the only response I have to smelling garlic wafting from someone's kitchen window is "mmm, garlic" and, to your point about that, I have smelt garlic from kitchens in the UK.)

Looking to restrict the release of cooking smells is therefore unreasonable. Doing so on the basis of "asian food is smelly" is therefore an unreasonable restriction that most severely impacts Asian people, which is discriminatory.

My illustration about my own experience is not supposed to be an exact allegory for the situation we're talking about but it is supposed to illustrate that generally people are far more receptive to culinary multiculturalism than you seem to be.

What if we stack up playing music from phone speakers:

• playing music (somehow) is normal, reasonable, everyday activity
• it is practical to keep the noise to yourself, and (with the right headphones) is comfortable
• the impact on others is difficult to rank. It can still be positive (if someone else likes whatever you're playing) but there are number of factors making it unlikely: phone speakers sound awful, especially from some distance away; other people are likely trying to listen to something else like a conversation or trying to concentrate and may have no way of blocking the sound out themselves. Public transport normally smells bad by default but I have no trouble having a conversation or concentrating on something.

So I think it's a useful comparison and illustrates how the two activities should have different expectations.

This is a bioessentialist broad generalisation that doesn’t hold true when you consider how many people hate places that have many people.

It could well be, but we're talking principles here like, "you should be invisible to your neighbours." If your principle is contradicted by a broadly true generalisation that we're social creatures, then it's a bad principle and you should get rid of it. And consider that maybe it's not a general principle, but rather your own preference not to talk to interact.

I don’t make assumptions of bad faith about random internet strangers and I’d appreciate it if you did the same

I assumed bad faith because I have never heard anyone calling garlic a "weird" ingredient before and still don't believe you think that. And I'm not trying to "diagnose you with mental illness"; I asked if you're autistic because it would give some useful context to your perspective for both of us. I'm not going to tell you that you are if you don't believe yourself to be.

Isn’t unseasoned grains boiled in water more of an asia thing, like rice?

It's universal. Rice, yes, but also noodles, pasta, various kinds of dumpling like Grießknödel, and semolina pudding. The list goes on.