When I got my driver's license (in Australia way back in 1988) I was taught to not sit behind vehicles that block your view. If it was safe to pass, then you should overtake them, or if it wasn't, you should drop right back so that your ability to read the traffic ahead was not obscured.
I adopt pretty much the same approach when I am cycling. Usually, the vehicles blocking my view are London buses, but in recent days it has been tall cyclists.
Now, I don't know whether you've made the same observation, but there seems to be a lot of tall cyclists out there. I never used to notice them, so I'm not sure where they have all come from.
But then I'm not quite sure whether they are tall people or whether it's simply that they are sitting on high-mounted seats. But most of them look slightly awkward because they seem so far off the ground.
The worst bit is that if you are trundling along behind them they block your sight lines so it's impossible to see what's going on ahead — are there traffic lights coming up, tricky junctions to negotiate, pedestrians you need to be watchful of, etc etc. And if they are wearing a bulky backpack, good luck in being able to take a sneak peek around them.
So, if you get stuck behind a tall cyclist, my advice is to treat them with the same respect as you would for a bus or a truck: overtake them if safe, or drop back so you can see the view ahead instead of getting an eye-full of some tall chap's sweaty back for the whole of your commute.