Well, then I am another anomaly and data point. I'm using ear plugs for 30 years at least 95% of nights. Never ever had an ear infection.

Me too, 20 years without a single ear infection and without a single day without ear plugs

I have found it depends on how comfortable the earplugs are. If I feel they are uncomfortable in the ear, there is a good chance I'll get an infection/inflammation in the next few days.