You have no clue what a red line is, apparently.
Hint: The USA drew a red line in Syria too. Several times. And every time, they backed down.
Now read something from your own experts:
By 2030, South China Sea will be ‘virtually a Chinese lake,’ US study warns – Asia Times
We are building up, and apparently no one wants to stop us. America in the 1990's would not have allowed it, but they have changed so much since then. They can't even hold their red lines over developing countries.
Nobody in the entire world takes America's "red lines" seriously anymore. That's why we are able to keep building and militarizing islands in the SCS.
You have no clue about "YOU GO!" Nobody takes China's "YOU GO" seriously anymore. Not the Europeans or even the Australians.