I have installed PHP_Codesniffer extension to find out the magento 2 coding standard issues. I have run the below command. "phpcs --standard=Ecg --extensions=php,xml,phtml --report-full=/path/testing.log /path/"

This extension lists out many errors in the log file from default magento 2 itself.

So, kindly let me know how to say that the default magento 2 coding standard has so many issues.