Exorcism question?

there is a question that i have regarding this..i know alot of different churches do exorcisms and such and not to single out any church cause i respect them all but i am really confused on why when the Catholic church does exorcisms they use the cross signifying the death of jesus, because he did die on a cross...to cast out the spirit.....they say that in Jesus name i demand you to leave...but doesnt the cross represent how he died? so wouldnt it make the demons happy?....just a thought...please answer maturely and dont be rude i respect all religions im just a tad bit confused about this.