The real Chilil hashem here is not what was done, In every group there are always people who do the wrong thing and nobody can really be responsible for wrong doing by others
The Chilul hashem is the cover up and the denial of the wrong doing. Harboring such people makes everyone else look bad and like they did the same things wrong. People will associate the whole community with these people and assume everyone else are doing the same thing.
It would be better off if you would admit they did wrong and tell those people the same thing you would to someone who had unfiltered internet in their house or drank Chalav Stam and throw them out.