True, all true. But none of this should prevent us from sometimes questioning whether there could be subversion from within. I'm thinking about faulty ISL translations of the liturgy, or the gay subculture in the clergy, or flaming liberalism taught in seminaries, or the mal-conceived notion that the Latin right was thrown away at Vatican II (rather than supplemented by the option of the vernacular). If the Vatican does things which seem in error, and which are not backed by declarations of infallibility, what is a Catholic of good conscience to do? Just go along, or ask why, or what?
Acquire a conscience, informed not only by knowledge, but by humility, both spiritual and intellectual. As Flannery O'Connor says, you do not reform the Church by saying "the Church is corrupt; I'll have none of it."
No one who allows himself to be quoted as kissing off the institutional Church is a Catholic. The present evidence suggests that Mel Gibson is just another idiosyncratic movie star in love with his opinions. As such, I don't see the point of discussing him on a Catholic thread at all, except as an object lesson in moral vanity.