Actually Protestants have as much agreement on fundamental doctrine Salvation, and sin as Catholics do.
Look around your church and see that 50% of Catholics do not go to mass on Sundays, thus rejecting the church rules. Look and see how many have 2 child families and see the rejection of the ban on birth control . I could go on but you know what a cafeteria Catholic is. Every one of them is actually their own denomination .So do not crow too loud :)
There's a difference between a rejection of basic Dogma and a difference of opinion on teachings. The Catholic church encompasses a "catholic" point of view with varying rites -- the Syro-Malankar, Syro-Malabar, Maronite and Latin being examples. There is no difference of basic faith as in the case of the myriad Protestant groupings.