They already filter for swear words, yet now the abstract idea of "trolling" is on the table and you will be able to filter any tweet containing a word you don't like. This is literally exactly the way China will not let you speak badly about politicians, except now people will not see any opposing views to their party of choosing. If the country wasn't split evenly it could soon turn into a one party system because you can't even debate or criticize those who would disagree with you on one of those widely used methods of expressing opinion. Instead of announcing you opinion to the world you will soon be announcing it to only people who already agree with you. Not good for any kind of debate, political or otherwise. That is how you create opposite extremists.