ujm:
You are presenting a narrative,, and I believe that a good bit of it is untrue. Let’s take it apart.
First – define mesira. This is about police reporting. It involves the alleged or suspected commission of a crime. This would involve arrest and potentially prosecution. And there are certainly times when this is the matter at hand. But there are numerous others. I suggest you seek some numbers for how many reports to State Central Registry are rejected, how many do not involve arrests, and what percentage do. Then tell me how many of these were in violation of a psak halacha (or would have been had a shailoh been asked). Not all government entities are subject to mesira.
Next – research the therapists to see if they ask shailos. Enjoy your sleuthing. Every single frum therapist would respond in the affirmative to such inquiry. Whether they actually do is another thing. How about if they already know the answer? Many therapists actually do, having spent considerable time with noted poskim, reviewing the parameters, and are experienced in knowing when the answer is simple or complicated. These therapists then pose the challenging ones for psak halacha. I have yet to hear of a single instance where a frum therapist went against such a psak or acted without having learned from poskim how to conduct their work.
I was not addressing instances where secular law conflicts with halacha. I will quote several poskim, notably Rav Dovid Cohen shlit”a of Flatbush, who paskened that a mandated reporter is obligated to follow secular law, and should report anything that the law of land requires. You may call Rav Dovid to verify this. He stated this publicly many times.
Lastly, your narrative usually assumes that the average posek is qualified to respond to these shailos. Well, that is actually not true. Most are not, and will usually refrain from responding. Do bear in mind that the typical shailos you are implying are double edged swords. There is either an obligation to report or it is completely ossur. The determination of the fact pattern is not made by the posek, but rather by the professional.
You should connect with some poskim who are versed in issues of mental health. They are typically connected to several professionals, and have amassed a great deal of experience in these matters. You can voice your concerns, and you will discover that the narrative has quite little merit.