There are many valid reasons to have trash cans cleaned:

Dirty and smelly trash cans are the most unhygienic item in the home and attract insects and pests, including maggots, cockroaches, flies, rats, mice, ants, spiders, opossums, and raccoons. The trash and waste materials inside the cans offer these insects and pests food and shelter, which can result in breeding and infestations. Once the insects and pests are attracted to the trash cans, they usually end up entering the residence, which then transfers the germs associated with trash and waste materials from the cans to the inside of your home. Many of these insects and pests also carry hazardous microorganisms such as bacteria, viruses, mold and mildew, germs that could result in disease, and other health and safety issues. Even after the trash cans are emptied, pungent odors and waste residue full of unhealthy germs are left behind. Cleaning trash cans regularly ensures foul smells and health hazards are minimized.

In addition, California is in a serious drought and state law along with regional ordinances prohibit bacteria-filled water from entering the storm drains, making it problematic for residents to clean their own trash cans without having a system that conserves water by reclaiming and filtrating it for reuse.