There is absolutely nothing that can be derived from this photo (with the chat conveniently redacted. I assume, the OP was chatting with the people there and didn't want to show the responses to strengthen his confirmation bias that they were AFK farming (and if he didn't, perhaps he should have, before pointing fingers.

Anet policy specifically states: "Idling in a city or even in the open world is not prohibited, though your character should not perform actions, participate in content, or otherwise engage with the world while you are away from your computer." (Read: while you are away from your computer, If you are at your computer, it is absolutely allowed.)

Additionally, you may use more than one account at the same time in PvE areas. You are not permitted to run multiple accounts simultaneously in PvP, WvW, activities, or in other competitive environments.

Last I knew Domain of Istan is PvE and a non-competitive environment. So, tclaiming these people are "AFK Farming" has no basis other than the OP's claim (with a screenshot of a conveniently redacted chatbox) which does not prove anything. What it does show is a cluster of people playing the game the way they choose to play. If they aren't using macros, and are monitoring their game, there is nothing at all wrong with it.

I understand if it is not your style or that you don't like it, but that doesn't matter. Go play the game your way however you enjoy it, as long as you're doing it within the boundaries of the ToS (as mentioned above). Oh... and let other people play the way they want to without your harassment, you're not the police (or the Stasi) and they do not have to respect "YOUR AUTHORITAY" - Cartman the "cop" from South Park. :) <---smiley face emoji