It's not just an opinion, it's exaggerated to the point of being factually wrong and bearing little resemblance to a reasonable point. I think the downvoting is reasonable. Here, I'll go through various points:

"You couldn't even sift through that shit in a lifetime, let alone use it all." "media assets you'll only ever use 1% of"

Assume someone's daily routine involves 3 hours (below average) of TV/movies, in HD. 5-6GB a day, 3TB is reached in under two years. 1% of 3TB is reached in a single week. Even hanging on to a small fraction of the media they watch for future viewing/sharing would fill up 3TB in a handful of years.

"Making full disk backups and archiving huge collections of media assets you'll only ever use 1% of is just a huge burden of mind and a huge loss of portability and flexibility."

Managing full disk backups means buying a disk and pointing an automated program at the folders you want. Average time per week: 0 minutes.

Managing huge collections of media assets: This means navigating services to click on movies and shows to download, and occasionally moving a season into a different folder. Average time per week: 5 minutes.

Burden of mind: Remember to buy a drive every several years, otherwise none.

Loss of portability: Keep it on an external drive if you want portability? Not sure what is meant here.

"Not to mention a waste of time and money."

Tell that to anyone with basic cable, as far as watching the content goes. Storing it after watching has negligible additional time/money cost.

Now do you see what the problem is with that comment? While it's certainly possible to be a digital hoarder, having two shelf's worth of movies on a hard drive is extremely weak evidence toward that.