Most people understand 'gg' as being 'good game' therefore I do not really see the difference in saying gg compared to good game after a match. However it can be seen as rude if someone types gg after completely destroying someone in the match.
gg
You ask a question in the title, just to answer what you think is right seconds later. Why even make the thread? Btw (or is that too rude, let's go with by the way), it's not rude at all. You're simply a person who doesn't want to accept that everything doesn't happen the way you want and for some reason you seemingly have a dislike towards Indians.
Ever since yahoo chess, I noticed gg. All of this urban slang has ruined the internet to a huge degree.