Wearing headphones while hiking is uncomfortable, and wearing earbuds for any length of time is always uncomfortable - hiking or not. They also fall out.
As others have said - not really a big deal. Either get ahead of them and maintain a significant distance, or stay behind and do so.
It is a big deal. It means for a lot of people there's nowhere they can go to actually enjoy the sound of nature. The strategy of getting ahead or staying behind doesn't work when there are switchbacks or crowded trails. The strategy that does work is to get fit enough to go deep into the backcountry because the troglodytes that bring speakers to hikes lack the discipline to ever get that far.
No. Your first sentence is framed from the point of view of your own experience. Regardless, I will not tolerate sound pollution like this. It's one thing in the city, where noise is chronic and endemic. Bringing that into a natural setting is simply inconsiderate of others, and it is the inconsiderate person who must change their behavior, not the people who are being imposed upon.
This position sounds dysfunctionally non-pragmatic. What does not tolerating sound pollution like this look like to you? In what ways can you possibly enforce your will in such a situation that doesn't immediately turn you into a hypocrite?
There you go. Quite comfortable, don’t have to stick them inside your ears, and still allows you to perceive the sounds around you.
In the spirit of fairness, I’ll also share the cons from my experience: First is battery life isn’t as good as headphones. That’s somewhat obvious as they’re much smaller, but they will still last you the whole day so not really an issue for hiking. Second one is that because they don’t block outside sounds, they’re not appropriate for audiobooks/podcasts while walking in the city. Again, not an issue for hiking.
As others have said - not really a big deal. Either get ahead of them and maintain a significant distance, or stay behind and do so.