I think it's a combination of them not caring and the bulk of the playerbase not caring enough for them to consider it a high priority issue. It took Yoshi P being bombarded by RMT spam just to get them to implement a quick report function for RMT (Which doesn't even matter since whenever a bot does actually get banned or muted a replacement just shows up almost immediately). It's extremely difficult to get any kind of response about the matter from them, and every instance where they did actually respond, it boiled down to "Just keep sending in reports" (Despite that clearly not accomplishing anything of significance).

Hopefully that will change once the abundance of DoL/H bots compromise the integrity of the Ishgard Restoration rankings since unlike their dominance over the economy that serves strictly to inconvenience legit players and thus is less likely to be ignored.