Why does politics get mean?

Because politics matters, but the degree of political literacy - and of the numerical ability to put numbers in context - is alarmingly low. This makes people susceptible to rabble-rousers, who give them something to get angry about; at the 2015 election it was the 'benefit scroungers', then of course we got 'uncontrolled immigration'.

So you have, to put it crudely, angry, stupid people. Living and working where most of us do, we're sheltered from the worst of this in person, but the Internet brings a whole lot more into play, while simultaneously removing the inhibitions that moderate what most of us would say in person.

I think politics is in the intersection of the two Venn ovals: ill-informed passion and Internet disinhibition. But I don't think it's the only subject where discussions get ugly. I've frequented photographic forums where the adherents of the Nikon and Canon systems were far more concerned with putting each other's brands down than with sharing any useful information. And you can probably think of a place where making gentle fun of an underachieving car maker is as wise as poking an overweight crocodile with a stick. I wonder if there's a cake baking forum where the respective adherents of Kenwood and Kitchenaid mixers can flame each other out.

Try PpRuNe.  The arguments over whether Airbus or Boeing are better aircraft to fly are huge.  Bonkers.  As with other topics there are people who simply go for it, flaming others down from day one.  Others try to be more conciliatory, but the common denominator is the lack of physical response. You can abuse anyone behind the avatar of a stupid name on an internet forum.  Do it face to face and your face will be punched out.

Bizarrely, try looking at a conversation between a Jew and and Moslem about the Israel/Palestinian conflict.  Both know it could easily lead to physical violence, so the discussion is measured and careful, trying to understand each sides position, carefully putting the other side right on matters of fact and generally agreeing to disagree in a polite manner.  Watch the same conversation between a Jew and and Jeremy Corbyn supporter (usually a young, white, middle class, university educated person who has not had a proper job).  The Jew will act the same.  The JC supporter will be vile, intemperate, accusing the Jew of personally killing millions of Arabs, ignoring all attempts to be reasonable and measured.  And yet they have no involvement in the conflict.

This was witnessed in Manchester two summers ago at the height of the latest Gaza conflict. A shop selling Israeli made cosmetics was hounded daily for several seeks.  Tens of Palestinian supporters gathered outside the shop to protest and force the shop to close down, even though the shop is a UK business owed by a British person.  What was interesting was the counter demonstration organised by local Jews.  They tried to make conversation with the protesters.  The only ones they could have anything like a sensible conversation were the Moslems. The whites simply spat at the Jews and were eventually arrested (and in some cases jailed).  The whole affair created better links between the local Jews and Moslems - much to the Corbynista's disgust.

Who? the real you or the online you?

...just a minute, I'll ask.....