Least favorite of the three I have seen (Is there only three?). But if you go into it with the idea of being entertained and take it for what it is worth it is a good time.
Obviously the series requires you to suspend realism but that is even more the case in this one. A little preachy too ... also seems to want to equate the confederate flag to the swastika which was an amusing take. But it was entertaining. But I liked the first two purge movies so I already liked it going in.