Question: why theres a blacklist cap..?

[Risvertasashi]

This is like asking why we can only store so many items or make so many characters.

200 blacklisted names isnt much but you need to see the big picture so if say 50.000 players fill their blacklist then suddenly its 10 million blacklisted names.

That and even if they did increase the limit you would eventually complain why you only have 300, 500 or a thousand slots.

50000 players * 200 names * 25 characters = 250 megabytes. Not that much. Storage likely isn't the issue (if this is even stored serverside). Performance might be.