By this reasoning, some random EU country could raise co2 emissions, stating that China is even worse. Problem is: the Planet does not care about artificial, man made boundaries.
To your last question: Yes, you should feel responsible. Who else could be? The point is to be conscious about what you do. Not everybody can be the best version of oneself, all the time, me included. However, denial is probably the worst of all reactions to this problem.
Not only does moralizing often backfire, it has an embedding effect that prevents actual progress.
Also, quite often non-disposable objects feel much more pleasant to use: Cutlery, glasses vs. plastic cups etc., just to name a few, so promoting reusable products over single-use plastic crap is a win-win in my book.
I'd definitely add film cameras to that list.
All of these can be true at the same time: Changes to individual consumption habits will not save the planet alone; these changes can still make an impact in aggregate; it can still feel nice to use a film camera while at the same time considering the environmental impact and maybe limiting their use to moments that really matter and not just a novelty thing.
And if people really (re)discover their love for film: Buy a used film camera! You'll get infinitely better results than from a disposable camera and will be able to resell it for practically no loss in value.
I've bought a couple of vinyl records of bands/records that I really like, but would feel quite bad about buying every record that I like that way, since producing them and shipping them around the world does seem like a pretty big resource expenditure for something that a file on my computer can achieve in much higher fidelity.
> guess which photos live in the cloud and which adorn our bookshelves?
You're aware that photo printing exists, right?