I'd imagine it's possible bots that have taken root on this site lately - approximately the last year possibly year and a half - seemingly to suppress what could be considered, by sentiment analysis, "negative" news of anything or anyone conservative.

Or those who feel more emboldened to downvote than in previous times on this site; possibly to its growth reaching new demographics. However it feels fairly automated though given how quickly it occurs and the frequency, and how it seemed also to coincide with this last election cycle.