Earlier quoted context omitted.
"Commercial use" is clearly any work-related use. (You are also not allowed to redistribute it at all)
I'd really like to hear that stated unambiguously by someone at Cognitect. It just can't be right. No sane person would think they could enforce such a rule and no sane person would be scared to "violate" it. There's no trace of information indicating what it was used for or when. If there is, no one should use it anyway.
Stated unambiguously by someone at Cognitect: https://github.com/cognitect-labs/REBL-distro/commit/144acd0...