This species apparently has a reputation of being very aggressive when disturbed at the nest, even though it is one of the rarely-encountered species. Nearly every web page on yellowjackets has a special note about this species-"very aggressive" etc.

Can anyone vouch for this or know why this is-after all it has small colonies compared to the vulgaris species group yellowjackets.

I have had at least a half-dozen encounters with this critter.
These are without doubt the most aggressive, persistent, nasty bugs I have ever had the great displeasure of barely seeing (other than their crushed body parts subsequent to my slapping at them after stinging me). I have been stung standing dead still, 20' away from a nest at 8:00 on a cool morning. There was no warning, I just felt the hit slamming into my neck. Once they're after you it's war. My poor shepherd dog released seven of them from her coat after 150 yards back to and inside the house. My wife got them into her panties inside her pants. I've been stung over two feet inside four layers of clothing including a full length net/jacket.
Whoever took this photo was either very brave, a total fool, or wearing full protective gear. My guess is that this particular bug may have been injured or unwell in some respect or far from home to be sitting still for that long. They are unusually active for yellowjackets.

I too have been stung while standing still 20 feet from a yellow jacket nest, but get these wasps away from the nest and they don't take any notice of you. This picture and a few others of Forest Yellow jackets were taken on or near nectaring sites.
On the other hand, I've heard about how nasty Bald-faced Hornets can be, but I've photographed a nest with workers coming and going from a foot away without incident.