Also, the answer to your actual question is no. There’s definitely no way to block people from using any particular characters at the kernel level.

What you seem to be asking for is a way to absolutely forbid all software from writing certain characters to files, and/or from reading those characters. Aside from requiring that the kernel inspect all data in detail before letting other software have it, which would slow everything way down, it would prevent anyone from reading or writing binary data which happens to contain those sequences of bytes by coincidence. Binary data includes things like the programs which make the system work, so blocking those characters would be terminal

It ought to look like a bunch of □, which is the glyph generally used to indicate that the font has nothing to represent the character.

Specifically you’d expect U+25A1 □ WHITE SQUARE

You were asking for definitions, and I responded by pointing out that they definitely exist. The fact that you or I don’t personally come from a background which values those definitions doesn’t mean they don’t exist, or that other people don’t use them.

Various holy books, I believe. See also pescetarianism, which stems from the same place

It was pointed out to me a while back that the paradox of tolerance is only a paradox if you consider tolerance to be a philosophical position.

In fact, we don’t treat it like that. We treat it as a social contract, in which context it is no paradox at all to say that if you aren’t tolerant then other people aren’t obliged to tolerate you in turn