Life In 19x19

A game of go is a conversation. You can try to hold the type of conversation that you want, but you have to have a willing partner. Just as the terms of polite conversation vary from one culture to the next (or even from one group of friends to the next), so too will the expectations for a game of go. You can either learn to appreciate cross-cultural conversation or find like minded people to talk with.

And the moment one runs into a player who is much stronger, they stop making the right moves that one could learn from for one reason or another and start making moves they know they can't get away with during play with a same level opponent.

Without seeing the games in question, it's hard to tell if this statement has any validity. As others have mentioned, games with high handicaps require the other player to play more aggressively than normal. And there is nothing in the rules (or etiquette) of the game that says a player must play corner, sides, and then center. Certain servers also lend themselves to an all out fighting style; again, different cultures play differently. But you CAN learn from the moves the person is playing. Perhaps you aren't learning about "proper" fuseki, but you can certainly learn about life and death. Every game you play is an opportunity to learn. A game that you lose is generally a better opportunity than one you win.

Meaning he only wanted to play with me to score a fast win and keep his precious Dan grade.

This seems to be assuming the worst about the potential player. You could be correct, but perhaps he (or she) wanted to offer a teaching game to a new player. Maybe they just wanted to play a game and didn't care who the opponent was. If you don't feel comfortable fielding requests from different players, most servers have an automatch feature that will find an opponent around your level. IGS certainly does, which is what I assume you were playing on if you ran into a 1k+.

Strange openings can even be successfully applied in high dan games, as demonstrated e.g. in one of HayLee's videos: https://www.youtube.com/watch?v=wto_OpMe4Ak

I joined the DGS 19x19 ladder tournament specifically with the intention of finding weaker players to try to teach. Some people don't want to continue after the game, or even chat during the game, but several do. I have found a few people who wish to continue playing games after the ladder game is finished. If I did not challenge these people in the first place we could not continue. Sometimes I win by a lot, sometimes not so much because I don't push to win by as many as possible. But it seems like we enjoy the games regardless.

Fred you touched on several aspects of the game.

One thing I like about GO is the traditional respect and courtesy that go along with it. We have a 2 Dan player, in our Club, and he routinely bests, me with 9 stones. He never gives up even if he is behind and always fights to the end. (At which point he has made up the difference : ( )

But he is always willing to replay and discuss my shortcomings, look at other options, and so I never take it as an insult. He is generous in being willing to share his knowledge, time and experience with us lesser players. I try to do the same with players weaker than I.

One thing I have noticed with the club, is how different personalities perceive losses, advice, teaching etc...
What works with one does not always work with another. Perhaps since GO is an intellectual striving, one has to be particularly gentle and perceptive to other people when teaching. Peoples egos are very tied into it.

So play on, enjoy, and remember even sandbaggers benefited you with a tough game.