I think a distinction should be made between ATTACKING a chapel or priest, and NOT RECOMMENDING it.
After all, a priest can and should look out for the good of his own apostolate, or the viability of the chapel he has worked hard to build up. Can a priest be expected to "recommend" people attend another chapel?
However, the priest (layman, etc.) should be detached enough to be always HONEST with people, giving the real reasons he doesn't recommend attendance at "the competition", rather than making up bogus reasons, which are often little more than blatant lies.
He must necessarily be detached, if his motive is the good of souls. What should a priest care if a certain parishioner's needs could be better met somewhere else? As long as their souls are taken care of, a priest should be happy. Now if his motive is mercenary -- total numbers, worldly glory, weekly collection income, etc. -- then he will be jealous for every warm body in the place, acting like he OWNS each of them.
A local man reported to me that he asked Fr. Zigrang if it was OK to attend the resistance chapel outside San Antonio, and Father replied, "I don't recommend it." I asked him what reason Fr. Zigrang gave, and the man said that Father didn't give a reason. He "didn't recommend it" and left it at that.
See, I might disagree with Fr. Zigrang (since I represent that "competition" as it were) but at least I respect him for being honest. At least he didn't make up some half-cocked excuse such as "they are disobedient" or "they aren't legitimate".