Unfortunately, some of those syntax niceties the Garry's mod creator mentioned are things that have been identified as leading causes of bugs.
++ mutates a variable in place, has non-trivial pre/post behaviour (many junior devs don't understand it), and its brevity causes it to be used inline, which results in complex one liners.
String concatenation using '+' is not considered to be a great feature in dynamically typed languages. When you can't guarantee the types of the operands, it can lead to unexpected results. Pass in two numbers, and it this returns the result of the sum. Pass in two strings, and they're concatenated.
'continue' is a strange one. I just don't use it, and I'm not sure why anyone thinks it adds anything. It's like an early return, in that it can cause some difficulty in code comprehension.
So it feels a little like Lua is being criticised for making some good calls.