I'm not sure if is this what you meant, but you seem to be implying that the HOV lane should be treated like the left lane, i.e. for faster traffic. That's not the case....and if those "left-lane bandits" have moved all the way to the HOV lanes, it's a least one more vehicle out of the regular lanes.
It's one of the drawbacks of the HOV lanes if you get into the lane thinking it's going to go faster. In light traffic, you're probably better off in the regular lanes if you generally like to go faster. I usually drive around 120, and move into the passing lane only when it's faster than the middle lane (passing other vehicles). When there are HOV lanes, I'm usually in them but if I don't think the HOV lane is going to go at least 110 to 115, I won't bother. If traffic's heavy I will be in the HOV lane and content to just coast along. Despite the fact that so many still cut in and out, it's a lot less likely someone is going to suddenly veer into your lane they way jackrabbits bounce around in the regular lanes. That's why I think bikes should be allowed in.