Free champs of ARAM

Why must I be forced to play the free champs in a ARAM. I realize you are randomizing but honestly if I didn't buy a champ I have no idea how to play him/her. If you want to have a competitive game why are the free ones allowed to be in the mix. If I wanted to try out a free champ I would play bots. Isn't that what bot matches are all about? Just wasted my time and my team's time because I was horrible. Horrible on a champ I knew nothing about. I also feel that the free champs are heavily favored in the selection as well. I like the fact that you random your champs but only ones that I have purchased if they are free this week and i don't own them them take them off the list.