It is not criminal to _shoot/film_, however it is a criminal act to _publish_ videos/photos with people when they have not consented. There are many exceptions though (famous persons, people accidentally in the picture not being the focus, public demonstrations and other events — maybe not the best translations, just to give some ideas)

However as has been said, even without intent to publish there might be civil damages involved.

Yet how many millions of Europeans in countries with laws of this sort have appeared on Instagram, Flickr, TikTok, etc.? It may be technically the case but essentially no one worries about it--even those who aren't going to shove a camera in someone's face.

what do you mean? I doubt this law in Germany is broken very much. Entities care a lot about it.

Entities, i.e. companies, are pretty careful everywhere about publishing photos of people for marketing purposes (which any website is) without permission of some sort. Whether it's in the terms of attending an event or it's a stock photo which presumably has a release form. I doubt individuals in Germany are much less indiscriminate about sharing on Instagram, Twitter, Flickr, and elsewhere than they are most places. And German law has very little teeth if the people doing the sharing aren't German.

Wouldn't the statute of limitations for this be 3 years? At least according to https://en.m.wikipedia.org/wiki/Statute_of_limitations

That starts to run only after the injured person has knowledge of the infraction.