Two issues here. One is definitions, sickness behaviour is caused by the illness affecting the nervous system, its not about the affect of emotions on disease progression though that is also real and both interacting together can cause a negative spiral in my experience.
This is anecdote. It's not really my experience.
The other is that emotional lability is a commonly reported symptom in ME but different subtypes may have different experiences, we don't know, that's part of the problem with current criteria.
It's not in most criteria so, for me, that suggests it's not really that common.
Periodic paralysis is also described by pwME but that doesn't make it a 'common' part of ME for most people.
It might be unrelated, a secondary complication, a manifestation of a subtype or a sign of co-morbidity.
Most criteria have a set of overlapping symptoms, of which emotional lability is not usually one.
Many report emotional lability as a factor in ME / CFS along with sensory hypersensitivity to stimuli and other phenomena which I believe may be related.
That's your opinion, and 'many' is another of those weasel-words which isn't very clear. In my view, sensory hypersensitivity appears more frequently in criteria than does emotional lability. That doesn't necessarily mean they're connected (though CCC connects them, I've not seen that connection elsewhere).
I don't think we can afford not to be aware of these things, its not fair on the people who suffer from them to ignore them.
I agree mental health is important. No one is disputing that. The issue is whether it's a common part of ME or just something that sometimes arises alongside it.
I've seen no convincing evidence yet to suggest it's a common part of ME yet. (I am going mainly off criteria here, because there isn't much in the way of evidence otherwise.)
The CCC suggests emotional overload
may be a consequence or symptom of hypersensitivities and it's thoroughly optional, given as one of a long list of possible symptoms.
Oxford includes it as an optional secondary symptom (but notably has been criticised for being too broad).
But the ICC, IOM, Fukuda, four-item empiric criteria and NICE 2007 don't mention it at all. In my view, that doesn't really make it a common part of the illness by most definitions.
There's only one scientific paper here (most of the rest are pretty dated) and that says ME is only 'associated with', not that it encompasses, includes, requires. Emotional symptoms are associated with most illnesses because illness is devastating.
I also think that's Twisk giving his opinion, and that paper was written by him alone. Most of the criteria written above were formed by a committee of people so there's more consensus there.
Above all interventions should not be trying to ride roughshod over natural responses which are adaptive and palliative care should facillitate ME patients in coping with their condition not impede them. IMHO that is the problem with leaping to an unjustifiable conclusion of dysregulation as the authors of this paper did.
I agree.
I don't wish to be alone, so that's a 0 then. And I don't wish to keep still either - just rather limited in how much movement I can do. I don't feel depressed - I've had clinical depression in the past, so am damn sure I know what that feels like. Aaarrrggghhh! 
@spinoza577