I am a regular chess player with over 400 ranked live games(I have earned quite enough trophies while I was in youngsters) and dozens of thousand quick games( blitz ones) online .
I also did manage to take participation twice in Greek stratego tournaments in November, whereas I have 1 year experience in online stratego so I think I know enough about this topic.
As far as the live game I have my below thoughts on this subject.
1.--> Yes that it is true by far in chess in relation with stratego. I had seldom experienced occasions when the opponent said something other than "I offer a draw" as the rules of FIDE are strict on disturbing the opponent by any kind of distraction. I don't think that they do it because of some kind of fairplay though.
2.-->There are some occasions though that some players behave in not in appropriate way in chess when they eventually lose their game. I have faced unappropriate behaviour from both young people and adults ones.As far as I know I didn't face any kind of such a problem on my stratego limited live experience.
3-->The underestimation of an opponent does not have to do with learning chess. There are a lot of occasions that a better player loses just because he/she does not play his A game to an inferior. It does have to do with the personality of the player more.
4--> Yes, that is true indeed , whereas in junior school championships children play till the end because it is possible that the table will turn at any point of the game despite the material difference(equivalent to 4+ additional upper officers). I think that the reason it does not happen in stratego is that there is different time limit than in chess.
6--> Clock is a part of playing chess too, so "unrespectful behavior like a waiting clock's end" is not such a bad behaviour. Time management should be an important factor for this game as it is in stratego.
7-->That it not true dear Spectre. It does also have to do with a person herself/himself rather than what game she/he likes to play. It is the extrinsic motivation that make them proud for numbers/leaderboards/money instead of the game itself.