1) Perhaps the most relevant cause of our skepticism/cynicism is Rome's track record. The largest persecutor of Christians has, historically, been the Catholic church. The church in its prime was notorious for its violence, deception, and meddling in world affairs - which largely contributed to the atheist movement via French Revolution and of course the Protestant Reformation. Although the inquisitions and crusades are over, there is a dark blemish on RCC for this reason alone.
2) The status of the Pope is dangerously close to, or even outright blasphemy. The position has been titled "Holy Father," and "Lord God the Pope" in history. Vatican writings also accentuate his assumed supreme authority over all Christians, that he acts and speaks on behalf of God, and that he is implicitly infallible. Such an ideology has led to the events of my first point.
3) Mary is a goddess in the Catholic church, being named "Mother of God" and believed to be in greater authority than Christ as a result. She is seen as a mediator between God and man, when the Bible explicitly says that this is Christ's position alone. Mary is also believed to be sinless. The deification of Mary and demotion of Jesus is heresy.
4) Idolatry is an infestation in Rome, who encourages bowing to/kissing the statues of Mary and the saints in addition to praying to them. Not only is this idolatry, but the practice also constitutes communing with the dead or necromancy - which is vehemently condemned in Scripture (a crime worthy of capital punishment acc. Leviticus). Evidently, praying to the dead is an act God hates.
5) The Catholic church teaches the doctrine of Purgatory, where souls/spirits are able to be prayed or bought into heaven. It also rejects salvation by grace alone, but believes that man must do good works in order to earn salvation. This has oppressed many true Christians and prevented them from having the peace that comes from being forgiven and loved unconditionally by the Lord.
6) Rome believes that the bread and wine of communion turns into the literal flesh and blood of Jesus Christ. Therefore, it encourages actual cannibalism.