You have raised a logical interpretation and I've no doubt it is valid. However, it seems both interpretations have some validity. I found this interpretation of Matt 18:9 in the NABCE " These verses are a doublet of ⇒ Matthew 5:29-30 [Cpilot - which deals with adultery and lust]. In that context they have to do with causes of sexual sin. As in the Marcan source from which they have been drawn (⇒ Mark 9:42-48) [Cpilot - which seem to be focused on heretics rather than lust] , they differ from the first warning about scandal, which deals with causing another person to sin, for they concern what causes oneself to sin and they do not seem to be related to another's loss of faith, as the first warning is. It is difficult to know how Matthew understood the logical connection between these verses and ⇒ Matthew 18:6-7." Certainly, you raise a good caution for all of us. It is dangerous to interpret a bible verse without some background, context and direction of the church. The Catholic Catechism is also a help in this but like all comprehensive texts, it too should be taken as a whole and not parsed to support a specific agenda.