If the priest truly says this, and the OP is *entirely certain *that this is not a misunderstanding because the priest has repeated this teaching himself in front of a group, then I have to agree. The concern ought to be brought directly to the vicar of clergy for the diocese. Do not pass go, do not collect $200, but let the bishop know in writing. Maybe this priest has a misguided desire to be “easy” on people (which is bad enough), but maybe it is worse yet. If it is worse, it could be very much worse, and very harmful.
I say this because this priest’s bishop would have to be concerned upon learning about this teaching that the priest might be looking at porn himself or giving himself a permissive reading of moral law with regards to chastity. It is not unusual to find, in retrospect, that the priests who fall into these serious offenses themselves were also teaching others that offenses against chastity are not so serious as all of that. The internet is so ubiquitous, sexual license is so rampant, these temptations can be a danger for priests, as it is for other men. There is no one the devil would like to lure into the falsehood of these crimes than our priests. The persons that a priest might engage in unchaste behavior with could unfortunately also be people who come to him in an attitude of trust, vulnerable because they look up to him and feel gratitude for his pastoral care or great affection for him personally, because they are young, in difficult marriages, struggling with sexual temptations themselves, or the like. Heaven forbid that this is happening, but if there are any red flags, the vicar of clergy needs to know. On behalf of those who might be at risk, he ought to be told. What he does with the information is up to him, but send him a note. I don’t mean to press him with “what are you going to do about this?” but just to say, “I thought you would want to be aware of this.”