1) In some aspects it probably is representative of a lot of what I see on the roads. However it's also attrocious.
At 0:37 he should probably be fiddling about on the pavement, rather than the road (although it's not really a serious misdemeanour, I'm sure we've all done it).
Strictly speaking at 0:41 the car shouldn't be in the cycle lane (solid white line) but realistlcly speaking there are all kinds of reasons (good and bad) why a car might be in them and they don't do much to help cyclists. (They can be helpful for routefinding, junction navigation (when done well) and reminding drivers that cyclists may be there, but in such situations painted cycle logos (often on a coloured background) are much better because they give neither drivers nor cyclists a false sense of security nor can they lead drivers to try and force cyclists into the "cycle lane". So far as I can tell the Declan is at least as responsible for that car being close to him as the car driver.) (That particular junction looks like one of those annoying ones that's almost but not quite wide enough for two lanes that car drivers treat as a two lane junction - imho better to get rid of the cycle lane and make it a two traffic lane junction - at least people know where they stand then and it won't reallly alter cyclists' ability to filter.)
At around 1:00 he should really be a bit further into the lane, rather than cycling along the white line (particularly has he was about to make a right turn), which is just asking for close/dangerous passes. He complains about a guy tailgaiting him - but that's probably better than attempting to overtake there would be.
At 1:16 I'd have probably dropped in behind the lorry (although if you are SURE the traffic lights won't change it probably would be safe to stop (well) ahead of him in the ASL there). He should probably have stopped in a more primary position at the lights, too.
At 1:55 why did he not just overtake the land rover on the right? What made him think squeezing down between the land rover and the bus was the better idea?
2:09 "Do you go, or do you not?" You absolutely do not. You shouldn't even be asking that question there.
2:46 The pedestrian probably shouldn't have been crossing in front of him but if that's a near miss/jumping out in front him in his books I dearly hope he never has to respond in a real near miss situation. Good road reading would have allowed him to avoid that woman with minimal disruption to his cycling.
2:59 Should have allowed that lorry to finish maneaouvering before passing it.
3:07 Similarly with the minicab.
3:16 The van clearly had priority. And trying to squeeze through the side before the van had finished cornering was downright dangerous.
3:48 The black cab driver was at fault (he shouldn't have overtaken before turning left); however in Declan's situation I may have yielded for him.
In conclusion: It is NOT representative of how one SHOULD cycle, however it IS representative of how many DO cycle.
2) A moral obligation? Yes. In some ways I would like to see a legal obligation too, but it wouldn't be popular (for many good reasons, I add) to implement.
3) It should be taken into account that people will cycle like that but planning decisions shouldn't do anything that would encourage that. I'm unsure where I stand on keeping people like that safe (I think of the segregated cycle lane down Tavistock Pl. where the cycle lane and the traffic lane were on different light phases. They had to change it to a single phase and no left turn for traffic because too many cyclists would go haring through the red light without even checking for left turning traffic in the traffic lane. Part of me thinks it's good that it's been made safer, but part of me laments the cost involved in the conversion and inconvenience to other road users routing (although on the plus side the lights now spend longer on green for the remaining phases, since one has been removed) just to protect a few people from their own stupidity (it also demonstrate certain inherent issues with such facilities that I won't dwell on here...).
Road/junction planning should be carried out in such a way that it both protects cyclists safety and encourages safe cycling (by which I mean something that protects people cycling badly shouldn't be done if that would encourage people to perform that maneaouver who otherwise wouldn't).