The guy on the V-Strom could have had hi-intensity bulbs and/or poorly aimed main beam. V-Strom and KLR650 etc. riders often buy all that adventure accessory stuff even if the only off-roading they do is on Safeways parking lot.
That aside, when riding behind someone for an extended length of time like that, it’s just plain common sense to dip the headlamp. Isn’t it?
On your other point, no, full beams should not be shining out in all directions.
If they are aimed too high, then you light up all the freeway signs for miles ahead, but there’s very little light going onto the road in front of you. I know, I’ve seen this on my current bike before I adjusted the aim downward (a vast improvement).
On modern faired motorcycles they can (and should be) adjusted both laterally and vertically so that at some point, the beam ends on the road (not off into the horizon). On all bikes (even old ones), you’ve got at least an up/down adjustment. I’ll bet if you look in your user manual, it’ll show you how to adjust your headlamps low and high beams.
I remember seeing cars in Europe with a headlamp beam adjuster on the dash to allow the driver to re-aim the headlamps when carrying heavy loads in the trunk.
Anyway, this has always been a controvertial point (full beams during the day or not), so I guess we can agree to disagree.