Twitter sometimes requires a verified email and phone number, which I assume they globally ban when they can. Not sure how effectively they are, but they do at least something make throwaways harder than Reddit does.

On Twitter you follow people, on a site like Reddit you subscribe to subreddits.

Switching between accounts on Twitter means your follows/followers are lost, switching accounts on Reddit doesn't lose you anything (unless you're subscrived to private subreddits or are a moderator for a subreddit)