Regardless of what the Reddit admins or Conde Nast are doing right or wrong to monetize their site, I think it's simply a matter of assessing the value of the information Reddit has exposed me to -- not just via the links but also the user comments. That aggregate value I've derived from their service over the past four years is still far more than what I just donated. (arguably it was more valuable a few years ago when there were fewer animated gifs linked on the homepage)
But that begs the question: if I'm paying reddit, why am I not giving back to the content authors that reddit linked to?