irs defines what a trade or business is:
The term trade or business generally includes any activity carried on for the production of income from selling goods or performing services. It is not limited to integrated aggregates of assets, activities, and goodwill that comprise businesses for purposes of certain other provisions of the Internal Revenue Code.
https://www.irs.gov/charities-non-profits/trade-or-business-defined
Rental property owners provide housing, not goods or services.
