Whilst we don’t agree with the Politics of Peter Mandelson (well most of us) , we also don’t agree with the antics of people who don’t agree with views other than their own, that its OK to attack that person with eggs, vomit green custard or even physical blows.
Politicians should be able to do their job, and express their views without fear of attack. This is what democracy is about. If you don’t like it vote them out.