You don’t get to limit discussions here to a set parameter that you try to set up and establish based upon “policies, historical or otherwise, are not mentioned in the article or post. In particular, there is no mention that Chinese warship presence is hinged to or dependent on the “Monroe Doctrine.”
The MD doesn’t have to be mentioned in the article to have bearing on this, but you’ve already set out to Poison the Well with your bad attitude so drop the bad attitude and be willing to discuss.
But since it isn't, a cogent explanation of how it's relevant is warranted.
Do you think Admiral Deepak is over there thinking "Aw shucks if it wasn't for that pesky US Monroe Doctrine against colonial expansion South America in the 1800's, I could rightfully be concerned about the Chinese empire's warships off my coast." ?