Been watching this thread with interest, having some experience of "the system" and broadly agree with the OP.
There is alot of misunderstanding of how things work in practise and threads I've seen about, for example, people vanishing down conspiracy rabbit holes often elicit the response that "sectioning" is the answer. Given the bar for that, generally speaking, is that a person is a danger to themselves and / or other people, what is apparently being suggested is detaining people whose controversial thoughts are inconvenient and discomfiting to others. Detainment under section is, rightly, a last resort these days, and rightly deserves clinical precision in its application.
I can see both sides of the argument, we have thankfully moved on from locking up people who might be considered "inconvenient" to family or the wider community. At the same time, the safeguards that legally protect us all from potentially spurious attempts to do so also create frustrating barriers for those who genuinely see a loved one heading down a mental health spiral leading to catasyrophic fall out all round, in getting meaningful support or intervention.
Much of the problem is due to lack of funding I think, and little understanding of how and why people do have mental health crises which can be organic, environmental, down to trauma etc etc. Complex cases can be box ticked in a way that complicates the issue, and in my experience, family do get a rough deal, especially with regards to the elderly where rights afforded by "having capacity" can be used to over-ride evidence that a persons behaviour is escalating to cause direct harm to others, but as it's not "criminal" they have the right to make those unwise decisions. If medical professionals are not allowed, at the patients request, to discuss their treatment or condition, it leaves people in a terrifying limbo.
"Getting someone sectioned" is not within the remit of anyone bar the appropriate professionals. One can suggest it might be a solution to an immediate crisis, but the process is vastly misunderstood and often seems utterly counter-intuitive to a lay person.
It's all a very fraught, often frustrating and sometimes tragic process and certainly not a quick and easy fix as some seem to think.