I think ghosting is really rude and immature. I knew someone who would keep saying I was their best friend (???) but whenever I would try and talk to them it would take 5-7 business days to get back to me. It was so unfair. So I cut them out. Granted I gave her plenty of warnings which only resulted in half-hearted apologies and broken promises. Not worth my time at all
The only times I ever actually ghosted people were because they were making unwanted advances on me, and even then it was at the request of my fiance.
On dating apps, I think a lot of people are really self absorbed and feel no sympathy for ghosting someone they hardly know
So in my thoughts, people ghost because they are either self absorbed, mentally ill, or were specifically asked to