If you consider yourself faithful to the authentic Catholic teaching, which is that abortion is intrinsically evil,
BUT you think most Catholics are unfaithful, then I don't see how you are "instructing the ignorant," "admonishing sinners" ---practicing the Spiritual Works of Mercy --- or in any other way
improving the Church, by leaving it.
Remember the Spiritual Works of Mercy?
Remember the "Church Militant"?
Familiar with the concept of "Spiritual Warfare"?
You seem to be in a posture of preemptive surrender.