How does a number offend you? I'm genuinely curious.
BLIDs are critically important to how Blockland auth and almost every server mod works. It's a common identifier to keep track of a user regardless of their username and keep track of someone across servers. The ban, admin, and super admin system work using them. Any sort of persistence utilizes them.
Even if they were to be removed from the player list (which they are by default settings), they'd still be accessible server side. Otherwise Blockland would be essentially unplayable. A banned user could change their name and immediately rejoin. That's not an enjoyable experience for anyone.