I read the last part of this answer and can't get what this sentence exactly expresses in the given context.
(Put them on your desk openly and write a mail that everyone can help himself.)
I would read and understand it as "mail to them that you aren't willing to help them as they can help them selves". But this would a) contradict to the answer's purpose and b) wouldn't even have any pertinence related to the treats.
I also can interpret that it probablly trys to state something like "Hey, if you want some treats, just move your self and get over here to grab it"
but I anyway can't get it how the given sentence could express that (or something in that way, as I still feel like not getting it right).