Poor performance on CoxWiFi hotspots, but local hotspot good. Why? How?

I'm a relatively new Cox internet customer. Had Comcast for 15 years before this. I work from home as a tech consultant, which means that I use WiFi hotspots at bars, restaurants and coffee shops every day. I've noticed some odd (in a bad way) behavior on the Cox hotspots. 

My computer will automatically log me in to any CoxWiFi hotspot that it finds. Sometimes that works great, but only when there is no obvious native (local) hotspot configured. In other words, if I'm at Joe's Pizza and they have a PizzaFi network (provided by Cox) and they also have a CoxWiFi network, my computer will automatically connect to CoxWiFi. That's what it should do, but 90% of the time I can't actually reach the internet, or if I do, the connection is terribly slow with high latency and packet loss. If I then switch to PizzaFi (probably using the same Cox modem/router) I get a fast, normal internet connection.

In a few places I can reliably use either the local named WiFi or the CoxWiFi and both give consistent, reliable speeds. But that's really the exception. In most places with multiple network options I can't use the CoxWiFi because it's so unreliable, even though it offers a strong signal.

I don't understand how, or why this would be happening. Does this make sense to anyone?