Sure, but that's a different situation to what I'm referring to. The slip road, leading to joining a motorway, is effectively an acceleration lane, allowing you, as quickly as possible, to reach the same speed as the traffic already on that motorway, which unless there is some type of hold-up, is mostly around 70mph, and in many cases faster than that.
Therefore, when I reach the end of that slip road/acceleration lane, before joining the motorway, I want to be matching the speed of the oncoming traffic (and thus be able to hit the fast/outside lane as soon as it's safe to do so), not be held back by some dithering buffoon doing 45/50mph, simply because he or she just wants to slip slowly into the inside (slow lane) behind all the trucks!
In that scenario, they're simply not only a bloody nuisance and an obstacle impeding my progress, but also not using the acceleration lane/slip road correctly for its intended purpose. The fact is, it's very dangerous joining a motorway travelling at a speed significantly slower than that of the oncoming traffic; the process should be carried out as seamlessly as possible, so these ditherers are bloody a hazard.
Marco.