I haven't generally seen that the trend in introducing dark mode has involved forcing it on users.

With most apps I've seen, it is indeed a choice. It's not a choice when someone records their dark mode screen/app and shares that content. There's a lot of very valuable tech education on youtube (people demonstrating frameworks, languages, etc.); when the kind people making those videos are using dark mode, some of their viewers are out of luck. That, and the conference talk projector example, are cases where it is not a choice.

So I'm encouraging people to consider their audience. If there is no audience, then one has only oneself to consider :).