"An idea is something you have. An ideology is something that has you."--Morris Berman

"Those who can make you believe absurdities can make you commit atrocities." - Voltaire, French philosopher

It should be self evident that if there is only oneness, then anything else that appears to exist, must have been made up. Furthermore it must have been made up for appeared to be a very damned good reason.

Thus instead of judging the world and everything in it, perhaps it would be more helpful for you to ask what value you saw in making it up in the first place. It may also be wise to ask yourself what would be a more appropriate response to it now.