If they're not damaging live trees or leaving behind 'garbage', then more power to them! 

I'd nominate the "Fred Flintstone" campsite on Opalescent for the title of Algonquin campsite with the best campcraft.  Someone managed to move a considerable amount of heavy rock to form two sofas around a large, raised fire pit.   The rock slabs that form the seats and backs of the sofas must weigh many hundreds of pounds.

I personally love it if there is no garbage and no damage no living trees or shrubs.
My friends and I usually try to make some kind of furniture piece. A small table between trees or a few shelves, backrests on benches, firewood shelters, things like that.

I'm not that big on lashings, but probably because my most recent experiences have jaded me.  

On Islet last year, where somebody left a lean to (the survival variety) just off the campsite, and lashed it with paracord.  I cut and removed as much of the paracord as I could see, but there wasn't going to be any dismantling that hurricane-proof structure. 

On Booth last Fall, there was a giant thing on an island site that (folks here helped me figure out) was for use as a chair, where you lay in a tarp or blanket on it.  It was very evident that live cut trees had been used in part.  Also lashed with paracord.  I dismantled it, added to the firewood pile that was there.

To me, those kinds of things are eyesores at a minimum, and of course nobody would promote the use of live trees.  That said, I have never complained about finding a little table at a site.  In similar fashion, I've never seen a nail in a tree and decided on principle not to use it for a clothesline.

For some folks I guess lashings is part of the fun, but for others it is probably a function of boredom at the site, and we've probably all seen the hatchety results of boredom exercised on large live trees at campsites.   I'll take the lashings.