There's a mute and block feature on Twitter and I advise Simmers to use it if they get upset by toxic tweets.
Information via Search
"The blocking feature on Twitter lets you restrict some specific accounts from contacting you, seeing your tweets and following you. Whereas muting allows you to remove an account’s Tweets from your timeline without unfollowing or blocking that account. Muted accounts will not know that you’ve muted them and you can anytime unmute them."
So, by muting, they can post as much abuse as they like but won't know you don't see it! It might do them some good mentally by getting rid of their upset feelings. You never know. :)