Because we're not bloody apes. We're people and we have feelings! And most of us don't even want to be here right now. Now, I'm sorry if you didn't sign on for the lot of us on the TARDIS, but there isn't much can be done about it now. No need to be rude.
I'm so glad you become nicer in the future because I wouldn't want to travel with you, otherwise.
Just consider that everyone here might have things going on back home or wherever or something they want to accomplish and won't take kindly on being referred to as bloody apes!
Keep it up and maybe I won't remember you back into existence at my wedding!