I'd say some of the limitations hit by Uber were real, and were a bit of a PITA even before that. Some were improved significantly since then, others still need to be considered when designing application accessing PostgreSQL.

I'd say it was a nice example what happens when you design application based on how you imagine an ideal database would work, not realizing that there's a lot of complexity and limitations. And then when you eventually have to face reality you blame the database for having to do trade-offs and refuse to mitigate the trouble by changing the application.