I got curious so I tried googling what concentration of sugar actually inhibit bacterial growth. According to this paper, it varied according to sugar type and bacteria species, but generally inhibition started at ~5% concentration for sucrose and ~10% for fructose. Popsicles can contain 15% sugar or more, so bacteria might not be able to grow effectively there, though growth still does happen.
I got curious so I tried googling what concentration of sugar actually inhibit bacterial growth. According to this paper, it varied according to sugar type and bacteria species, but generally inhibition started at ~5% concentration for sucrose and ~10% for fructose. Popsicles can contain 15% sugar or more, so bacteria might not be able to grow effectively there, though growth still does happen.