A: I’m not saying that it’s necessary to “remain silent” when someone makes what you feel are “outrageous claims”, but if you respond, do it in a polite manner and refrain from harsh accusations.
B: There are multiple truths. That is what makes Judaism so beautiful. Yes, it is a religion based on deeds, not faith like Christianity, but one’s time and effort is best spent trying to improve his/her own actions, not worrying about others’. We all have different nisyonos. For a baal teshuvah who has tasted pork prior to becoming religious and who remembers what it tasted like, it could be extremely difficult not to go back to eating it. Yes, all Hashem wants from us is to try, and despite our best efforts, we all slip sometimes. What seems to us to be unforgivable is an easy mistake for someone else. In the same vein, our struggles might seem silly to someone else. When I die and have to face the Heavenly Court, I want to be judged favorably and with compassion, so I will try to do the same for others here on earth rather than looking only for the bad and condemning it.