aikido isn't violent.
sometimes the people who train are though, and thats scary because aikido performed with violent intentions can be devastating.
i sometimes have problems with people who can be a little aggressive on the mat. i feel i dont want to train with them as even though they are sempai, they dont respect me as an uke. they think it is up to me to be able to take the ukemi for them even though they may throw in a way that i cannot take ukemi from or that is dangerous for me.