I agree. Unfortunately, not everybody has any politeness at all. Assuming they can speak English, they are just rude. But being rude isn't a crime so I suppose you have to put up with one game with them, then put them on your blacklist. Eventually, if like minded people do the same, they will all end up playing each other!
Suggestion; when you have a game and enjoy playing your oppo, maybe chatting during game, swap names of a couple of others you have each played and got on with. Birds of a feather ....
What is with these players who do not respond to challenges, or to messages? I have heard others complain about what they consider to be unsporting behavior in the form of taking too long to make a move. Given that we all have busy schedules keeping us away from this site, and given that some of us play many games on this site, thereby essentially forcing a delay in games for which the best move is not immediately obvious, this complaint seems a bit mis-placed. But is there any comparable explanation for a complete lack of any response whatsoever when a challnge is issued? Or, when a challenge is accepted, and one player sends a greeting such as "How are you?", is there any justification for the other player to not have the modicum of common courtesy required to even respond at all? Unbelieveable!