Christianity as a whole is a scandal. But, the hierarchy of the Catholic Church, the only true Church, is guilty of the gravest of scandal. Clearly it is known through authoritative Catholic Church teachings that abortion is murder and can be ascertained by any Christian through openness to the word of God. Church leaders have failed to teach the justice of active defense against advertised known murderers. They have also failed to encourage public protest, correct voting, etc.
Scandal gives cause or reason for another to sin, i.e., being an occasion for wrong doing.
Scandal and death are a product of failure to teach that all innocent human beings are worthy of defense when defense would save the innocent even at risk of losing ones own life. This is known through the second part of the great commandment, Love of neighbors as yourself. It is clearly seen in the story of the Good Samaritan that everyone is to be considered your neighbor. Self-defense is lawfully and morally acceptable by whatever means are seen as necessary. Self-defense is not however obligatory.