Jim Murphy hasn't given up. He has suspended his tour for 72 hours to take advice on his personal safety. He has even said that it isn't about the eggs, but the intimidation generally at his rallies.
This is about politics, and about stopping people from getting their message across. Rally-wrecking (either by way of eggs, organised mobs or filming private members of the public) does that much better than issuing idiotic threats on Twitter or Facebook (so, for that matter, does issuing veiled threats to academics and business leaders). What was Murphy supposed to do? Stand there like an idiot and continue in hope the deluge of ova would soon be over? If the media have indeed devoted more column inches to it, it's because there is more about it to discuss. By contrast, while I see Alex Salmond has been subjected to death threats - along with all public figures from time to time - the only possibly serious one had bugger all to do with the indyref campaign. Come to think of it, I don't remember the threats to JK Rowling being that big a deal - or at least not for very long.
Not that I want to trivialise this. I have been harassed in my job to the extent that I had to spend time at home with a security guard in a car outside. Not nice. At least I didn't have a dry cleaning bill though.
I agree with this:
"We condemn all forms of abusive, dangerous and offensive behaviour, whether it be Jim Murphy having eggs thrown at him, or Alex Salmond being harassed by a road rage motorist"
... except I would add "intimidating behaviour" too. That is what this is really about.