Sure they do, and the moderators, but it's getting worse.

Quite a few of the sub-reddits I liked went to shit over the summer when they made the API changes. The replacement mods aren't doing the same quality work as the original mods. What were nice sub-reddits previously are memified and gamified garbage now.

Users and (at least before the last run through the meat grinder) moderators.

They have human moderators who by and large care about maintaining the quality of the communities they moderate, and give those moderators buttons to delete posts and ban users.

Although FWIW, reddit seems to have it's fair share of astroturfing (at least, in my own anecdotal experience), it's just comparatively less egregious than rawdogging the google results.