While I completely agree with you that spending $4,000 on these slack bots is a waste of time, that is still a minute fraction of the cost of "unbillable" items listed by this article. Why not submit an FOIA request on one of the other items instead, such as the $140k spend on "developing the brand" and find out what actually involved? [0]
If you really want to be outraged by a waste of taxpayer dollars, I would recommend that you take a look at how much state governments are overspending on prisons vs education [1], wasteful spending in defense [2], and the $8.5 trillion in unaccounted taxpayer dollars spent on defense [3].