Because he's making bold accusations. He's stating most cyclists can't use roads properly. That they're dangerous. That they can't abide by rules.
Change the word cyclists to say...Black people, Teenagers, Women etc...see where it ends up?
Don't be a pedant.... seriously 'black people'?

What does race or social equality have to do with road use? Don't change the subject by trying to make unrelated and unnecessary connections.
In the case of the cyclists I encounter on the way to and from work every day.... he'd be right.
They abjure the dedicated cycle path along the bypass (built at great expense) and wobble about in nsl traffic. They blow through red traffic lights without even slowing down. They undertake cars and lorries, weave in and out of moving traffic giving no signals as to their intent - in one case the guy went the wrong side of a keep left bollard and rode directly into oncoming vehicles, just so he didn't have to stop (I see a guy on a moped who does this most days of the week too). They ride wearing dark clothing with no lights on their bikes along an unlit nsl road.
These riders are not the 'recreational' bunch you see hogging lanes at weekends in the summer pretending they're in the tour de france. They're commuters who don't give a damn about anyone else.
There's a couple of chaps I see every day who behave themselves and ride courteously, and most drivers give them the same in return. In fact I've observed these same riders being waved through and given way to by drivers who respect their consideration to the rules of the road.
On the whole, bar one or two notable exceptions, cyclists I encounter on my commuting seem to have no conception of the danger they present to other road users and themselves. Sure I might be better protected in my metal box, but if I have to swerve to avoid a weaving cyclist, or one who runs a red light (happened before, will happen again) and I have a head on collision with another motor vehicle traveling at 30-40 mph, that right there is a combined 60-80mph impact and a trip to A&E if you're lucky. What use is my metal box for protection then?
All it takes is a split second for everything to go so badly wrong. Most people involved in serious road traffic accidents always say the same thing 'I wasn't expecting it' 'I never saw it coming' 'It was just an ordinary commute to work, how could this have happened to me?'.
To put it another way - cyclists appear (I'm making a reasoned guess here) to take the rule that car drivers must be aware and give way to pedestrians/cyclists etc to mean that they have carte blanche ro ride in whatever manner they see fit, because 'it's ok, drivers will always have to make way for me'.
Whilst this is technically true it needs to be applied with common sense and courtesy.
Same goes for pedestrians crossing the road at T-junctions, who look at you turning off a main road into a side road, crossing over oncoming traffic, then they step out into the road anyway. You have to stop to avoid running them down, causing other drivers to stop also.
Placing your own safety in the hands of other road users courtesy and observation is not only inconsiderate, but reckless in the extreme.
ooh, turned into a but of a rant there lol.