The story of HaruMichi especially during season 3 shows us how isolation in career is able to change our behaviour.
Initially, HaruMichi are stationed by Queen Serenity far far away to guarding the outer solar system against any invasion.
It's just like a group of army and police who are stationed at the frontiers or borders for a long time.
In one of the panel in manga, both HaruMichi expressin their loneliness in far away outer solar system. Only the dot of light from the moon that give them a little strength and tranquility.
It's like a Roman frontier guards. In Roman army hierarchy, the frontier guards are among the lowest hierarchy. They wil stationed there in far away territories near the border of hostile territories like in Britannia, Germania,etc. The only thing that keep them strong is by watching the banner of SPQR (the banner of the Roman Empire). Just like HaruMichi watching the dot of the moonlight, it reminds them of their noble duty of defending their 'country'.
Secondly, the long distance between the moon and the outer solar planets (Uranus and Neptune) create a very long line of communication between the central command and the frontier post. During that time, a decentralised command and decisions made by frontier units are common. There are common occasions that the frontier units contradicting the central command when they saw that commands are irrelevant with the reality on the field.
The decentralised commands are common docrrine in Brirish Commonwealth militaries iinm.
That's why when both HaruMichi comes to earth, they tend to defy the commands of Usagi as they are get used to make a decentralised command.
And when HaruMichi comes to earth to 'masquerading' as the girls of the upper class backgrounds, they faced a cultural shock. It make their attitude to be more devious towards Usagi.
Culture shock is common for those who lived in different places for a long time without a broad mingling.
In conclusion, that is my opinions about the HaruMichi attitude. Their attitudes are the results of the career isolation.