Usual lack of clarity
Unfortunately, many articles like this – both on The Register and elsewhere – fail to be clear enough about the threat for people to understand whether they are at risk. In this case, the reader is recommended to disable or limit WAN-side management of the device, something that is not only common sense, but also typically the default. Given the mention of it, then, one goes on to ask "Does prohibiting management from the WAN side prevent this attack?". Because it either does or it doesn't; this should be black and white — but the reader is left confused.