Moshe Rabbeinu's Mussar

When Moshe Rabbeinu gives klal Yisrael the mussar schmooze of their lives - he makes sure to say it in a gentle tone and to only mention things by hint ( see first few pesukim of Devarim ).

Why ?

I mean, the purpose of mussar is surely to better the person receiving it ( providing it is both accurate and sincere - two qualifications we can easily attribute to Moshe Rabbeinu ) - so why beat around the bush ? If you saw someone's child ingest poison - would you tell them that " it might be a good idea to get to the doctor in case something ... " or would you tell it like it is ?!?!

So why is mussar different ?

[ According to the Alter of Kelm - it isn't ! He would teach this by example and genuinely thank anyone who rebuked him. After all, he said, this person is just trying to help me be a better Jew ! ]

For the most part - we don't take criticism well. Hashem gave us an independent streak that serves us very well in our ability to function day by day. However, this same self confidence will also rise up to defend itself against any onslaught. So the frontal approach for criticism is rendered ineffectual.
However, if the mussar is only hinted at - then when we discern the true meaning of the rebuke we are actually employing our own cleverness. So it is a win-win situation as far as our ego is concerned - either we were correct in our actions - or - we were clever enough ( with the help of others ) to figure out what we did wrong and correct it. The second option is much more palatable when put this way - thus enabling us to see past our ego and accept the rebuke.

On some level, Moshe Rabbeinu's greatest mussar to us was in how to give mussar - lovingly, and with as much care and concern for the recipient's ( perhaps fragile ) ego as we have towards their spiritual state. He was truly Moshe, Our Teacher.