How do you deal with mobile phone villains in movie theaters?

When I went to see Odyssey about a month ago, there was a villain
who kept checking their phone—maybe KakaoTalk or stock prices—every
10 minutes or so. Even though the people sitting right next to or
directly behind that person would be suffering the most, they
just endured it. Even though I was sitting a bit further away and
it was distracting, I felt awkward speaking up since I wasn't right next to them. I
endured it until about an hour into the movie, but I finally couldn't
take it anymore and told them to turn off their phone loud enough
for everyone around to hear. They apologized immediately, so the issue
was resolved.
It felt like everyone around me thought, "Good for you for speaking up." However, once
it was over, instead of feeling triumphant, I felt strangely uncomfortable
throughout the rest of the movie, which ruined the experience.
But today, I went to see Interstellar, and there was a person in their 60s
watching with a couple in the row directly in front of me. Even though they
had their phone screen set to dark mode, they weren't just checking it briefly;
they had it out and were looking at it for almost the entire movie.
I was about to shout at them to turn off their phone again, but since the Odyssey
screening was full, I had no choice, whereas today there were over 200 seats
and less than 10% were filled, so I just moved to a seat far away where
I wouldn't have to see that person... T_T