In regards to critique, criticism, and advice:
Then you say:
So consider exactly what you just stated now vs what you initially stated:
Critique can be outlining a positive (but may also outline negatives as part of the nature of a critique is to review and analyze both successes and failures), where a criticism is always outlining a negative. This would entail that all criticisms can fall under critiques, but not all critiques can be a criticism. Which if you noticed what I quoted you from above, is the inverse of what you previously stated - all Critiques are part of criticisms, but not all criticisms are part of critiques.
The nature of a critique is that you will be looking for areas of improvement or faults, where you have failed and succeeded. To give feedback. This would mean, tacitly, that to tell someone "Good Job!" on a clear, that you are critiquing their performance (even if it is positive), which under your initial statement, is a criticism and therefore "...doesnt change the fact that it's rude to do it in public".
Im being specific about this because I want to stop you from flopping about on criticism, critique, and advice and stick to one single position regarding it. So yes, semantics matter here.
Either way, you dug yourself into a hole. Youre subjectively qualifying what is an acceptable critique vs what isnt based on what you perceive as a positive - which can vary from person to person, or you maintain that all critiques are criticisms and therefore no nos. Either way, you run the risk of offending and being rude to the recipient. Even if you said "Good Job!" on a clear, they can take that as "Good Job? I sucked. Stop patronizing me." or "Good Job? What about all those other times?" or "Good Job? I did excellent. Stop putting me down."
In all cases, even your best efforts to not offend and mean well have been interpreted as negative results. Because you cant control what other people think. Even if it is ridiculous
For all your best efforts to avoid offence, you cannot in any way, shape, or form guarantee that you will. Which makes the whole idea of "Oh, its polite to not say anything in front of others if you have criticisms/critiques/advice/etc." moot because the foundation of your point is that you are trying to spare embarrassment, feelings, drama, or etc, but since you cant control this, and other factors are to be considered (like how your fellow players feel, or promoting bad play, or seeing the opportunity for a teaching moment in a co-op environment, or treating your fellow player like a mature adult, or making sure the run goes relatively smooth and not waste time,).
No one is suggesting being an ass. That obviously doesnt work.
What is being suggested that rather than being overly polite, making a ton of assumptions, and deciding discourse based on what someone else feels, to just speak politely but freely in the moment. Because it matters to everyone involved. You think someone may feel bitter for throwing out a suggestion or advice, think how bitter tehyre gonna feel when they wipe the group cause something they did wrong and no one bothered to say a thing up til then.