Real time programming requires you to be able to make hard guarantees about how long a certain piece of code can run and what resources it uses.
This is literally impossible with a GC because you can only bound one resource (time or memory) at a time.
The best RTS languages are a pain in the ass to use because the compiler will complain about everysinglething - cases that could go wrong with your code
They are used in mission critical (in all sense of the word) systems like spaceships - where a tiny bit of lag will send it thousands of miles in the wrong direction.
Those links you provided, one is a draft for a spec, it's not even implemented yet - and the other has nothing to do with real time languages.
Maybe it would be easier for both of us if you wrote the definition for real-time or systems programming, rather than just saying something isn't one or the other.
Look, a good systems language should have predictable assembly instructions that the code compiles into. You should be able to literally with your eye map from code to asm and jump back and forth in a systems level language. GC enabled languages don't have this property as the assembly would be littered with GC code to clean up things. You won't be able to map back and forth.
You will note that rust advertises themselves as a systems level language and it is deliberately designed with the term zero cost abstraction. All this means is predictable asm from code. No black magic. Rust is advertised as systems level and this is the property that enables it. I hope that allows you to understand what it means to be systems level.
I truly believe that you are completely wrong and only few languages nowadays are system languages without a GC. C++, C, D (when used without the GC) and rust are examples. All the other languages you listed aren't.
Hence, the word has different meaning from person to person. So there is no wrong, or at least it exists on a spectrum, and everyone complaining about the original comment's word choice is just jerking their ego off.
https://www.aicas.com/cms/rtsj
http://blogs.windriver.com/wind_river_blog/2017/05/java-on-v...