@John *********
No, I don't think that is the correct analysis. It's actually OK to work remotely on any visa (besides, the DTV has the exact same "employment prohibited" remark as tourist visas, retirement visas and certain other visa types).
Basically, the fear is that those on tourist visas or exemptions coming for "remote work" might end up overstaying or working illegally for a Thai entity. That's why, it's best to get a DTV for remote work as it was specifically designed for that purpose.
However, for a true holidaymaker/vacationer who just spends a month in Thailand and does a little bit of remote work, it's actually fine.