How to say "I disagree" in the 21st century

I dont think many commentators on this blog have much trouble in finding words in which to disagree, head on, full on, eyebrow to eyebrow (and usually with courtesy .. lets not forget!). But I am struck how often straightforward disagreement (a generally healthy state of affairs, which is often the bed-mate of broad agreement)  has been recently hi-jacked by a whole load of denials. I would like to put in a plea for good, old-fashioned diasagreemeht.

If you follow Twitter (or any of the follow up comments after Question Time or any such programme), you'll be familar with this one: "Mary Beard is out of her depth here", or only slightly more impolitely, "Stick to what you know, Mary". What this actually means is that "I think you are wrong", but as your day job is to teach Classics, I will say that there is this no point in hearing you on this topic.

It doesn't take much to see that there is a disequilibrium here. If Mary, as citizen, says something you dont like, then it's easier to say that she is 'out of her depth' than to confront her arguments (which may of course be wrong.. that's another matter) about migration, Corbyn, the EU or whatever. It's easier to say, "you dont know what you are talking about", than answer the citizenly question.

A slightly different version is the patronising line of "I am disappointed in you". I have come across this recently over the Rhodes statue. I happen to believe that the university system and its curriculum is far too white, but the statue of Rhodes should not come down (as I said before). I can see the other side of the argument on the statue, but I do not agree.  I actually think it's a more radical stance to leave the damn thing up.

That's why I feel particularly infuriated by the 'disappointment' line -- as if only the poor old dear got the point , she would see the error of her ways. The furthest reaches of this have been a bit mad. One tweet actually said, after the tweeter had pushed me to say that I actually knew someone who wasn't white (oh come on!), "On behalf of all white people, I'd just like to apologise again for Mary Beard." Another correspondent, a friend of mine, actually went so far as to suggest a course of retraining (or he would say discussion, but it sounded like retraining to me!).

At this point, I'd like to observe just one thing. That it is possible to disagree over all kinds of things (tactics, short term aims etc) without being enemies. That's life.

And, to push this a little further, maybe we dont want a world in which we all agree on absolutely everything,