Displaying whatever you want on your website is an established thing. It might not be a very friendly thing (unskippable ads, etc.), but it's ok. The user visits you for what you have to say, and you say it. Going to the candy store with your car and hearing the owner tell you about his new candy, or even his opinion about your car, is fine.
But having your car tell you, unprompted, not to go to this candy store, but rather to the one owned by the car brand, is nuts. It's not okay. How on earth can people equate these two things?
Because that's just an ad, literally the same as any other ad we've been conditioned to put up with for our entire lives. Drawing the line here but not "$company's thing advertising it's unrelated product with 1st party ad space" is silly. Every company shamelessly does this, you're just used to it. This the 1st party equivalent of your competitor buying an ad for your company's name on Google because they're an alternative, the whole industry spies everything I do online chasing this kind of ad targeting.
Everyone in this thread is made really uncomfortable because of the stupid digital fiefdoms we've created and complete lack of user protection we have and are now realizing how little control we have over the previously somewhat neutral staple apps we've grown to rely on. But there's nothing different about this, or your car for that matter. This is the conclusion of "it's their platform blah blah."