I know some hosts have had really bad experiences with other hosts. Sometimes it’s that they are nitpicky, as if they are comparing yours to what they think of as their perfect listing, and don’t give 5* ratings, sometimes it’s just the usual entitled guest behavior, like showing up with more people than booked for, sneaking in a pet, leaving a mess.
But I have hosted 3 other hosts and they were all great guests who left 5* ratings. They all happened to be home-share hosts, like me, who I think tend to be more laid-back, accepting people in general.
What I think is that hosts aren’t any different as guests than the general public is. Some will be great, some will be awful.
It’s assuming that they will be good, respectful, understanding guests, just because they are also hosts, that’s the mistake.