You are using someone else's pure heart, messing with their emotional and mental health, to mend your own and to heal your own emotional and mental health, and that makes you an abusive person. There is no sugarcoating this. I have done this to a few men too. I received my karma and I immediately contacted them to undone some of the hurt by giving them the closure that they thought they needed but truly all they needed was not closure of the relationship but for me to give back what I took to them. For me to acknowledge the abuse I caused them and for me to mend their mistrust in the world and in love.
Anyone who accepts to be a rebound is someone who was already emotionally vulnerable and for me to use them in their moment of vulnerability makes me a major jerk. Women do it all the time but they rarely hold themselves or each other responsible.
For someone to accept to be a rebound, they must have been in a very fragile phase in their lives and I took advantage of that.