That may be because they are riding gravel roads on them and not going down any steep/technical singletrack? Even riding down the steepest gravel road where I live I stay seated.
Doesn’t mean anyone is right or wrong just that your use is different.
Both can be right. Although I end up taking my CX bike down a lot of technical (for a CX bike) trails, Swinley blue and red, local singletrack, etc. Yes a dropper might help, but for me it would kinda defeat the point of having a fast, lightweight, but not particularly easy to ride bike. It’s meant to maximise the number of will I / won’t I make it moments on a ride and the speed/comfort opens up more local-ish trails.
So a dropper isn’t wrong, but if it’s right then why not a suspension fork, 70mm more reach, riser bars, 2.2″ tyres, etc as well.