Because...  

If that's all you have then there is a very good reason you can't do anything else besides fly helicopters.  Have fun with that...  The message was not a threat nor meant for any particular person.  The intention was that if someone feels like they deserve better then they should find a path and go for it.  There is a better life out there and life is short.  But here we are once again with someone who stubbornly refuses to exercise understanding and pragmatism by completely acting like a man child.  And THAT is exactly the point of the reply.   Loudest voices have the smallest minds...   Sounds like you should probably stay right where you are!