SSPL is appealing for business but it is not open source. That is a deal breaker for us. We want to remain open source under a license that is recognized as open source.
Foundations run in a more non-profit, community-oriented way include the FSF, EFF, and Debian, none of which made any significant comment. Debian has excluded SSPL software, but their criteria for inclusion are stricter than simply "is it open source?" and they announced it was simpler to replace them with their superior non-SSPL equivalents than to actually tackle the question.