Remember, Meditations was written by Marcus Aurelius as a sort of ongoing “note to self” while he was the Roman emperor, essentially the most powerful and influential person in the western world at the time.
He’s not lecturing someone else. He’s exhorting himself, calling for his own best, reminding himself of the kind of man he aspired to be. He could have gotten away with murder, much less selfish and boorish behavior.
Which makes passages like this (3.5) so remarkable:
“How to act:
Never under compulsion, out of selfishness, without forethought, with misgivings.
Don’t gussy up your thoughts.
No surplus words or unnecessary actions.
Let the spirit in you represent a man, an adult, a citizen, a Roman, a ruler. Taking up his post like a soldier and patiently awaiting his recall from life. Needing no oath or witness.
Cheerfulness. Without requiring other people’s help. Or serenity supplied by others.
To stand up straight—not straightened.”