But if you dig a bit deeper, you'll find out that he soon after became a member of the far right UKIP party and was considering running for MEP. Also, his YouTube channel had over a million subscribers, of which his girlfriend was not one. So the reality is not that he's just a Scottish comedian, but rather he's also a far right political wannabe using his platform to spread anti-Semitic hate speech in the form of "jokes".
So perhaps "making anti-Semitic jokes for your girlfriend" should be treated differently than "making anti-Semitic jokes for your million YouTube followers"? At the very least, that is what happened here.
It's also important to note the context that there is a massive and growing online hate speech problem and has been for several decades now.
The arrest does seem to have radicalized this guy. But he's just one person, and he was popular enough to get support from a ton of famous people, and no doubt his million YouTube followers. I would need to see more data before I can form an well founded opinion on whether these arrests work or not. Perhaps they do work as a deterrent for the kinds of people that don't get Ricky Gervais publicly standing up for them.