Got similar meltdowns on the Killie forum. It got pretty nasty and there's still a lot of it going on, though it's moved on to SNP guys baiting Labour. Very tedious!
The thing is, well this is my opinion ( other opinions may differ!) that it's just human nature to argue, everyone likes a good old argument. It used to be you'd do it face to face, if you disagreed with someone you'd sit and debate, put your point across and attempt to either coerce or understand the other person, it didn't always work and sometimes you'd never agree but it rarely got nasty as there was a human face staring back at you. These days we're all to an extent faceless, we can sit and dish out abuse with impunity, there's no concequence to our actions so people just unload knowing that they will have zero comeback. A five minute google search will provide you with any opinion you choose to believe and there will be thousands of like minded people willing to provide 'facts' backing up your viewpoint so everyone's an expert now. It's a shame to say it but the basest parts of human nature seem to appear when people know they have nothing to lose by being a knob.