I can't remember exactly when r/conspiracy starting being brigaded, I just know it was a bit after Reddit changed. Before 2016 Reddit was a lot more normal, and skewed more libertarian, even supporting Ron Paul a few times. However, the day after Hillary Clinton won the Democrat primary in 2016 it's like Reddit changed overnight, like a switch was flipped. It was incredible to see. There was this massive influx of bots and shills, supported by the most of the mods, admins, and execs at Reddit to push "the narrative", and that has continued ever since.

It's really funny too, because sometimes there are moments that the shills haven't gotten their updated programing, so they back off Reddit until they get their new marching orders. One such time was when Hillary passed out at the New York 9/11 memorial in 2016, which looked really bad on video, and for an entire day after the event Reddit returned back to normal and everyone was amazed with the change, but then the day afterward the shills and bots returned.

R/conspiracy used to be one of the few mid sized subreddits that was free from brigading by bots and shills, but that began to change, and it's slowly gotten worse over time, to the point that now they've almost completely taken over, and most of the genuine users have left.