I don't see your moral high ground here. Snapchat never opened their service and then closed it on you leaving you stranded. They have a service that you reverse engineered knowing it was a closed service and they sent you a pretty nice letter asking you to stop. Should they have made their service more secure? Yes. Does that give you the moral high ground? Hell no.
But, I personally wouldn't worry about it. If they really felt strongly they would send something to GitHub asking to have your project removed. If GitHub takes it down that means they are either being douchey and covering their butts, or they believe the request has legal merit.
But, I personally wouldn't worry about it. If they really felt strongly they would send something to GitHub asking to have your project removed. If GitHub takes it down that means they are either being douchey and covering their butts, or they believe the request has legal merit.