“Not all victims of molestors are girls, many are boys.”
What does that have to do with anything? In this case, they were all girls and they weren’t molested.
“If you wish to call a Shmiras Halashon if a known molestor attends your shul with your nieces and nephews (Or any other relatives), go right ahead.”
That has nothing to do with the example I cited.
“I will protect my family first and if it means I did an averiah, I will take that averiah. Better I take such an averiah than anyone become a victim”
That shows a big lack of emunah. If a certain type of hishtadlus is assur according to halacha, doing it won’t help you a bit. Hashem is the one who decides what happens. Our actions don’t make things happen, and it is kefira to think that they do.
As the Mesilas Yesharim says, our hishtadlus is muchrach (required) but not mo’il (causative).
The Chovos Halevavos says that if someone does hishtadlus that is against the Torah, it shows a lack of bitachon. If you think that acting against Hashem’s Will will help you that means that you think that you are in control and not Hashem. You think that your actions make things happen, and not Hashem.
If you had lived in the US in the early 1900’s would you have said it was okay to be mechalel Shabbos because otherwise you wouldn’t have a parnassah and your kids might starve?
In any case, if you know that the guy is a molestor and that a specific person or people is going to be coming into contact with them, of course, you are allowed to warn them. But that has nothing to do with deciding that you can make public announcements online because you heard that a certain person might be a molestor even if you don’t know that they are a danger or that your announcement will protect anyone. And even in the example you gave, you would still need to ask a sheilah in order to find out exactly what you are allowed to say and how to phrase it.
“And people who cheat in their taxes (I dont mean take an illegal deduction, I mean serious cheating like not paying sales taxes or paying employees in cash) are likely to be dishonest elsewhere as well”
To think that you can make a public announcement condemning someone who cheats on his taxes because otherwise someone might end up being cheated by them is absolutely absurd. Maybe I should say that if someone makes statements reflecting a certain lack of emunah, then I could assume they might end up being dishonest since they think that their parnassah depends on their own hishtadlus so I have to tell everyone about them?