Yup, by the rules as written and this ruling alone, yes. Thatsxwhy I griped at the answer.You can't expect the writer of Sage Advice to actually read the PHB! However Stinking Cloud doesn't actually prevent Actions, it says "You spend your Action Retching & Reeling", so bonus could still apply I think.
Notice the division however between stinking cloud and the Warlock Shadows invocation.
For the Warlock, the ruling is that "until you move or take an action or a reaction" include bonus actions because "Bonus actions are actions."
But for Stinking Cloud (and presumably all those "only action is Dash" fear type effects) "On a failed save, the creature spends its action that turn retching and reeling."
Bah... at my table, "Any effect that forces a character to spend its zction in a certain way - such as Dash or retching - counts as "anything that deprives you of your ability to take actions also prevents you from taking a bonus action.""
Although, one could argue by RAW Stinking cloud "deprives you of your ability to take actions" since you cannot Dash, Attack, Disengage etc etc and the "deprives" does not say "anything that deprives you of your ability to take ALL actions also prevents you from taking a bonus action."
But its cleaner as a house rule for me.