Accused of being 'rude' for talking before the game starts

So I'm fairly new to the game, I joined on October 19 and have played 11 games so far, so I may not know all the unspoken etiquette of the game, but today I was accused of being rude for simply sending messages before the game started. The player who accused me has over 55 games played and says:
When I asked why he considers it rude he said:
This seems like madness to me, is this really standard etiquette in the game?
Many players, myself included consider it rude to talk before the game is finalized and starts
When I asked why he considers it rude he said:
Because I don't know if you'll stay, this conversation could be a waste of time, which I find rude"
This seems like madness to me, is this really standard etiquette in the game?