I have always let my bikes idle and warm up a bit before taking them out and riding. Even after a light warm up I ride them slower and easily before just ripping on the throttles. I would recommend this to anyone as well. I wouldn't say that its hard on parts because I do not 100% know that to be true.

However I also don't go out in the morning start my car/truck and slam the gas peddle to the floor before its warmed up.

Like Jerry said everything wears in these motors just by normal function. That is just how things are. That is why maintenance is very important. The fluids and oil only stay clean and clear until your first ride. hell mine usually gets dirty after the first startup after a fluid change.