Season 6 is a rough watch because it's very topical. The show in general is, but watching the justice system so thoroughly fail someone--especially a woman of color--is so realistic to what happens in the real world. Season 7 is much the same, as it deals a lot with ICE detainees on top of it all.
It's some sad trout, and while I feel like the series has always done a good job of bringing levity, it's not an easy watch when you realize everything being portrayed is really happening right now.