The 501c3 tax exception is specifically for charitable organizations, and the law and IRS interpretations exclude a number of groups that would colloquially fall under that description. On top of that there are many groups who aren't doing charitable work, but want to reinvest all revenue back into the organization and not be beholden to shareholders (private or public).
That's not true. Charitable organizations are just one of many groups that qualify as a 501c3.
Groups dedicated to scientific, literary or educational purposes also quality.
The reason this is a problem is that Rebble is using their being a "non-profit" as a point of advertisement but there is essentially no difference between someone owning a for-profit company, and someone controlling and heading a non-profit company where they set their own salary and are not a 501c3.
