The ones against any kind of monetization at all are already vocal enough, let alone the people who would balk at anything that monetizes user data.
If you look at their change where they introduced affiliate link rewriting it's really surprising. They did it in a way that made sure they wouldn't affect any 3rd party apps, they gave everyone 2 ways to opt out, and didn't rewrite links that already had an affiliate code. And yet even with all of that, there was a ton of outcry and anger at the change.
Reddit as we know it won't be massively profitable, because the vocal users of reddit are so completely against any form of monetization.
There will always be vocal minority which will never be pleased, no matter what you do. And later they forget it and move to other thing. Sometimes you just have to carry on with your plan knowing that you will lose some users, but aiming to do better overall in the long turn.
It's important to listen to the users. What's even more important is knowing when to say 'no'.
Yeah, no matter what there will be naysayers, but the majority of comments in the announcement thread for the affiliate links thing were negative.
Combine that with the reddit demographic's love of a controversy (no matter how trumped up) and you have a ticking time bomb that makes mistakes hurt for much longer and much worse than most platforms.
Just look at their previous "algorithm change" fiasco. They changed the front page algo, and after about a week they changed it back because of outcry. For the next several months people continued to complain about how everything was worse now, and that they were lying about "reverting" the algorithm. It's insanity.
Reddit was successful in the early days due to the quality of the comments of its userbase. It got diluted after the user base expanded.
However, qualifying it as toxic only means that if you were head of Reddit, you would probably run it into the ground like Digg.