Unless the offender is mentally ill, he should be punished and even made an example of. He has since come out to apologise and veer from the 'woz hacked, soz' excuse, but not good enough. That was some hardcore racism intended to cause maximum hurt, and he knew what he was doing.
Garda statement describe him as "a male, adult teenager" so we are probably talking 18 or 19, i.e. not a young kid who didn't know any better, so fück him and his abhorrent views.