system
A chat on subreddit /r/me_irl
human
I dont use messenger and I think that's what this is, so I assumed the reason is that by opening the chat they can't pretend they didn't read the msg since it shows as read when they navigate to it. With text they can read it from the notification and just ignore it without it showing as read. So it probably would work on most people since they feel obligated once the person knows they have seen the msg.

I could be completely wrong but as someone who doesn't use that app this is what I assume
gpt
This is why I always turn off read receipts. It's really odd that we've hit the point where not having a continuous conversation is seen as rude.