I think I see your point... though the "What can be destroyed by the truth, should be" quote, I always took to be limited to the world of ideas; i.e., any idea that can be... should be.

But as has been remarked before, the more you load an aphorism down with caveats, the worse an aphorism it becomes. Or as Shakespeare famously said: "Brevity - in speech and conduct, but not in any other senses of the word - is the soul, understood metaphorically & non-dualistically of course, of wit."

So while I see your concern in principle, I'm not too worried. I really doubt that LWers actually take this quote to mean you have a moral duty to, for example, visit old widowers and widows and berate them for the stupidity of talking to their dead lovers. Or find out and reveal the USA's nuclear launch codes. Or forcibly "out" every young LGBT person they know.