[gond]

Justifying doing something wrong by stating that someone else did equally bad or worse is not a valid argument.

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.

[posterman]

its... wrong to use a disposable camera?

[23B1]

This is a silly argument made by environmentalists for decades now, often to promote failed policies; plastic recycling, ethanol subsidies, and most egregious the prevention of progress around nuclear power.

Not only does moralizing often backfire, it has an embedding effect that prevents actual progress.

[lxgr]

The other end of the spectrum to moralizing is completely negating any personal agency over resource consumption that each of us has. And unlike for things like "flight shaming", there is an alternative here.

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.