If you think that identifying privilege is to dismiss an argument, rather than to demonstrate its limitations--well, I would suggest some reflection about what is leading you to that assumption, 'cause that's not what vidarh is doing. It's not rhetorical, but rather functional--an understanding of sociological privilege is effectively a requirement to have a meaningful conversation about any of this. That, not "oh, you're privileged so I will dismiss it", is the point of asking these questions and why they matter: to demonstrate the shades of gray and the limits of perception that are
necessary to have this conversation without ending up swamped in reductive pointlessness.
Nuance always matters. Context always matters. You won't derive meaning without them. (And if you aren't trying to derive meaning from something, if you're just aiming for the reptile-brain blood rush of Airing That Opinion--frankly, there are easier methods to replicate that that don't involve bothering other people.)
And while I am emphatically not accusing you of anything in your post, my experience has led me to the rule of thumb that the fear of such a rhetorical dismissal, as you expressed, stems from a desire to dismiss out of hand something challenging. It is in almost every case I can think of a do-unto-others-before-they-do-unto-you defense (even when, as is generally the case, nobody's doing unto you in the first place), so I'd personally think pretty hard before being too holy about it and telling vidarh what's frowned upon here.