Good question. I think it's because I just rolled into it. It was not really a conscious decision and after a while I got used to its quirks. And it got significantly better over time too of course.

I started on Oracle, then spent many years on MySQL, and am now using mostly Postgres. I vastly prefer Postgres over MySQL. Mind you, I haven't really worked with MySQL in a few years now, so it might have improved a lot for all I know. The one thing that initially drew me to Postgres over MySQL was DDL being transactional.