Parsing unfair but okay?

[Sylve]

Statistics, of course not. But it’s fairly common knowledge that a lot of the crafting/gathering and PvP bots continue to go unpunished in this game.

Bot ban waves happen irregularly because if SE were to ban a bot the instant it gets discovered, the bot makers just change it immediately and create a new bot account.
By allowing them to run for some time and the banning in huge irregular waves, it makes it a bit harder for them to change what got them caught.
It also concentrates illicit material in comparatively fewer bots.

There's also some bots that get put on watchlists so they can trace the legit account that is the source player for the bot accounts.

If it helps any, think of it more like drug busting.
Sure, removing the dealer as soon as he appears on the street is good for the community. But unless they take down the supplier, a new dealer will pop up every day.
So they watch the dealers to catch the suppliers.