We designed the 100 account limit intentionally to reduce the “dragnet effect”, something other bulk blocking tools have encountered in the past. With the “dragnet effect”, once an account is added to a block list by one person — regardless of why — that block is often copied by other people who use the same block list.
Although that account may not engage in behavior that would cause other people to block them, they will still be cut out of the conversation because of the original block. This is most likely to happen with very long shared block lists, which are harder for individual users to check before using.
As a result, we’re introducing this feature with a 100 account limit per block list, though we may reevaluate this limit in the future.