I accept that I probably used a very broad brush with that comment, and some cab drivers are not guilty of the sort of behaviour I mention, but I can only think of three occasions when I have had a positive experience: One cab driver anticipated well, and paused to let me out (which he should have done anyway, following HC); one cab driver talking to our ride leader on a Southwark Cyclists ride (he was a friend and also a cyclist), and a cab driver commenting favourably, and joking with us about the tandem as we were riding and keeping pace between junctions along the South Circular (he was an ex-cyclist).
On the other side of the balance, when I cycle to work, I experience the most frighteningly boorish and downright dangerous behaviour from black cabs. Yes, I get the odd bus driver being a pillock, but, in the main, they drive pretty well, considering they're piloting a house through the traffic. Van drivers? Yes, they're a very mixed bunch, with some horrendously bad driving. But Cab drivers are the ones who are pretty consistently bad, offensive when challenged, and (quite correctly) tell me there's no point in reporting them, as no action will be taken.