one of the primary complaints I've seen is the Tesla apps being inaccurate about charger availability - like 4 out of 5 chargers available here! And you show up and they're actually all taken with a huge line of people waiting.
In fact, mid drive Tesla will auto-reroute you to a supercharger station with more open slots if the one you're going to gets busy while on the drive. The UI is extremely accurate (like I can see open station numbers increment when a car pulls out).
Are you sure you're not hearing complaints about non-Tesla chargers?