I couldn't care less whether Suarez tried to stay on his feet or not. He was tripped by Guzan and it was a pen.
I've been saying this for years, if an attacker is fouled but stays on his feet then the ref won't award the penalty. They're scared to make decisions and if the player doesn't go down that's their excuse not to give the foul. Until officials start making decisions based on the challenge rather than the reaction, I have no issue with players going to ground when they could have stayed on their feet. In fact, officials are encouraging it by not awarding fouls when a player stays on his feet despite being fouled.
Then he dived, whether it was a foul or not. 'Going down easily' is just another way of saying diving.