I think everyone understands that. It's not necessarily a good idea to insult the player though; especially when they aren't actually doing anything stupid. When you die or do badly in a game it's fairly crucial for the player to be clear about why. In the best games you always blame yourself; in lesser games you tend to blame the game.
Of course it is. Particularly when the game is apparently familiar but the rules have changed.
My game Sticky Balls got some criticism because you could complete a table with pretty much zero skill just by blasting the balls about. You got a crappy score of course because the game was about 'score mining' each table but some people just didn't get that; because there was level progression so they felt that completing levels was the aim and thus the game itself was pointless. Those who understood what we were trying to do really liked it but are the level blasters wrong to find the game pointless? And even if they are wrong, they are potential customers so it's my fault if they fail to get the point.
I make the comparison because the problem was my unusual rules on an apparently familiar game style. Now I quite deliberately used the familiarity of pool\snooker to draw people in so I can't moan when people are upset that there are significant differences.