I'm more familiar with CSS than I am with Lua. The syntax for the former has a very different meaning[1].
[attr~=value]
Represents elements with an attribute name of attr whose value is a whitespace-separated list of words, one of which is exactly value.
! is commonly used as the unary not operator, so "a != b" makes sense as a shortcut for "!(a == b)". a not equals b.
But in Lua, the unary not is written as “not”.
For a language apparently inspired from Wirth, one would have expected <> (greater-or-lesser-than). But the real horror, to me, is Windows not letting one disable the so~called "dead keys" easily.
I get you are taking the piss but ~= is just as logical as != being the symbols for: "not equals", if you've been exposed to some math(s) as well as ... well, ! means factorial, doesn't it?
Syntax is syntax and so is vocabulary! In the end you copy and paste off of Stack Exchange and all is golden 8)