wanker
You are being so binary about it.
You can't see anything wrong with your stretch of cycle lane (even though by your own admission it is used by non-cyclists, puts you at risk of being run over by a car turning left, and leaves you having to risk crossing a busy road) therefore ALL cyclists should use ALL cycle lanes ALL the time.
So firstly, we have to decide what the purpose of cycle lanes is. Is it to keep cyclists safer, or to keep traffic moving faster?
I will eat my hat if you can find a single council which has said they have installed cycle lanes in order to allow cars to drive faster on roads. Which means their primary purpose is to keep cyclists safer.
For you, safer = separated from cars.
Safer for me achieved by staying a safe distance from the kerb and encouraging drivers to give me enough space when passing me. For me, a cycle path where you have to stop start stop start, dodging kids on scooters and then cross a busy road isn't safer than riding properly on the road.
And frankly, my default position is to avoid cycle lanes, because the majority of them aren't fit for purpose. So if I'm cycling somewhere for the first time, I'm not going to 'test out' the cycle lane, because I already know there is a more than 50% chance it will be less safe than the road, for my style of bike and riding.
So then we get down to consideration. For you, it seems that anyone not able to stay at the speed limit for the duration of their journey is inconsiderate, nay selfish.
However, it is only cyclists that appear to get your wrath on this.
As I have said before and will say again, what about people looking to turn right, who stop and wait for a gap in the traffic to turn. Are they selfish for holding up traffic behind them?
What about a driver who stops to let that car turn right, therefore holding up traffic behind them? Are they selfish?