Health-And what I’m telling you is – Rav Moshe is a Chiddush regarding cooking in a microwave -you have no proof to apply this elsewhere.
To be a D’oraisa it has to be similar to Meleches Hamishkon -cooking in a crock pot ISN’T similar!
There are at least a couple issues at hand-
1) issur bishul of the heating elements
2) issur bishul of the cholent
You may argue that the heating elements don’t reach the deoraysa -glowing red hot- level, although according to the famous chazon ish, “chatzi shiur m’doraysa” and therefore even if it will never glow its still an Issur deoraysa.
Even if that wasn’t an issue, the cold chulent even if completely cooked would be ossur deoraysa to reheat, because of the Issur of Bishul Achar Bishul Be’Lach (liquids). However, if the chulent is hot, if it isn’t fully cooked yet, there is still the simple Issur of Bishul. As long as something isn’t cooked fully you can be OVER on bishul deoraysa. So no, you wouldn’t be able to tell a goy to turn it on in these scenarios.