Hi,
Avast! members can only do so much in 1 day. One day they might have 200,000 viruses (Actual). The next they might have 10 (Actual viruses).
One would allow to cleanup issues like this, the other will not. It's all, what is and isn't priority. Something like a modern version of CIH is obviously more important then, an-easily-removable piece of adware.
Edit: I'm not saying it isn't "important". I'm saying in contrast to the potential workload, it is less important then other potential issues that may (or may not) arise.