A lot of bloggers seem to be socially inadequate, pimpled, single, slightly seedy, bald, cauliflower-nosed, young men sitting in their mother's basements and ranting. They are very angry people.
OK – the country is full of very angry people. Many of us are angry people at times. Some of us are angry and drunk. But the so-called citizen journalism is the spewings and rantings of very drunk people late at night.
This is someone in a glass house firing numerous stones of various sizes in all directions.
Firstly, and most obviously, attacking people for their appearance is cheap and low, and that goes doubly for elements of appearance that are not of their choosing. It's a cornerstone of why we oppose racism, sexism, homophobia, disability discrimination and so on.
Within that, however, consider the fact that Marr himself is not what many of us would think of as a looker. I'm willing to bet he was that mercilessly abused jug-eared lad at school that everyone called FA Cup.
He is perhaps outstripped in these stakes by the phenomenally ugly John Sergeant. Yet this has nothing to do with the quality of their reporting, even though they're on telly. With bloggers, they don't show you what they look like so it makes no odds whatsoever.
And because we don't see bloggers, we get to the serious point about Marr's charges. He doesn't actually know this stuff. He's just listing a variety of things we say about people we don't like, without any evidence. So much for his implied moral high ground of authoritative opinion.
It's notable that these accusations of warped male friendless nerdiness are exactly the same things that were said ten years ago about anyone who used the internet. They were ways for the people who saw the rise of online communication as alien and threatening to pretend they were above it.
By the same token, the mainstream media is feeling the ground shift under its feet, hence these outbursts from Marr and colleagues. Their old certainties, their aloof position, their power to publish where the only available space for retort was a Letters page controlled by the same publisher, it's all been swept away.
Which brings us to another problem with what he says. Yes, there is a lot of ill-informed, vile, misanthropic, intrusive stuff on blogs. Of that material, much of it is intentionally written that way. In this respect, it is no different to the tabloid press.
For Marr to talk as if reporters only write things that are considered, beneficial and true is to pretend that the best selling newspapers in this country have never existed. Such vitriolic, speculative, seedy tittle-tattle is the public's preferred flavour of reporting.
But to look at The Sun and use its standards as grounds to attack the likes of Charles Moore and Nick Cohen is ludicrous. So it is that our repulsion at the putrefying mass of tabloid-equivalent blogging is no basis for attacking the medium as a whole, let alone making Marr's snidey snipes. The lack of real facts in his criticism only underlines that point.
The stuff I love in blogging is the way that, every day, there are news stories dismembered. The bloggers walk you through their reasoning and cite sources that are credible. It's like a forensic version of The Day Today, teaching you to use your critical faculties with news media, keeping your bullshit detector at full power.
All those stories about how 'they're trying to ban Christmas' and making people call it Winterval in case it offends muslims? Not one of them is true. Likewise lots of the stories about immigration. But you wouldn't know that if you only read the papers and watched TV. It's when bloggers look into it that we get the truth.
There are large elements of crossover, because responsible reporting is essentially the same endeavour whether it's bloggers or professionals. Channel 4 News' Fact Check blog does a superb job of correcting what we're told, and conversely news broadcasters pick up rumours from blogs and turn them into stories. Last year there was something going round about Gordon Brown being on certain pills. It didn't appear to have any real foundation, but that didn't stop it being inappropriately being included in an interview by one Andrew Marr.
It appears that, fingers burnt, he's blaming bloggers for telling him to put his hand in the fire.