According to Catholicism, why did the robbers strip the traveler to Jericho? At Luke 10:30 (NRSVCE) we meet the traveler to Jericho who was saved by the Good Samaritan,  in a vivid narrative given by Jesus:

" Jesus replied, “A man was going down from Jerusalem to Jericho, and fell into the hands of robbers, who stripped him, beat him, and went away, leaving him half dead.""

One is eager to know why Jesus made a mention of robbers stripping the traveler. They would have done it to search for hidden purses. Or, Jesus perhaps wanted to give a benefit of doubt to  the priest who would naturally  take the traveler  for naked and dead, therefore `double-unclean'. I therefore, wish to know the importance of Jesus' mention of the stripping and beating of the traveler to Jericho. Do the  teachings of Catholic Church say anything about it ?
The robbers represent the demons, the fallen angels, who take advantage of man fallen into sin:

From the Catena Aurea on Luke 10:


  AMBROSE: But who are those robbers but the Angels of night and darkness, among whom he had not fallen, unless by deviating from the divine command he had placed himself in their way.


and


  AUGUSTINE: He fell then among robbers, that is, the devil and his angels, who through the disobedience of the first man, stripped the race of mankind of the ornaments of virtue, and wounded him, that is, by ruining the gift of the power of free will. Hence it follows, who stripped him of his raiment, and wounded him, and departed, for to that man sinning he gave a wound, but to us many wounds since to one sin which we contract we add many. 


The priest and Levite signify the Law of Moses, which cannot free man from sin:

Explaining Luke 10:30, the 1582 Rheims New Testament commentary says:


  
  Half Dead.] Here is signified man wounded very sore in his understanding and free will,
  and all other powers of soul and body, by the sin of Adam: but yet that neither understanding, nor free
  will, nor the rest, were extinguished in man or taken away. The Priest and Levite, signify the Law of
  Moses: this Samaritan, is Christ the Priest of the New Testament: the oil and wine, his Sacraments: the
  host, the priests his ministers. Whereby is signified, that the [Old] Law could not recover the spiritual life of
  mankind from the death of sin, that is, justify man: but Christ only, who by his passion and the grace
  and virtue thereof ministered in and by his Sacraments, justifieth, and increaseth the justice of man,
  healing and abling free will to do all good works.