Mind if I geek? I'm going to geek. Sorry.
The way I look at the title, is that it makes good sense under what appears to be the album's concept. Trent (or the concept protaganist, whatevs) is in a good place - evidenced by a funky, dancy lead single - but is troubled by wounds (whether physical, emotional or in relationships) and bad memories from a darker time in life. We know there's a major retrospective element to the album, with the reprisal of Downward Spiral's font, artist and emphasis on physical art. That album culminated in the contemplation of suicide and a life misspent.
Now it would have been more tasteful to title the album "Old Scars" or similar, but Hesitation Marks continues that theme of harking back to TDS, and is arguably less on-the-nose as it's an obscure term.
Or then again, maybe I'm barking up the tree and Trent's just delivering a huge middle finger to Flood by expanding Just Do It into a full LP. But probably not.
I do get Sheepdean's point though. There's a reputation for NIN fans to be chronically depressed self-harmers. While I suspect that doesn't apply to most of us, it's a sentiment which hasn't just appeared from nowhere, and it would be a vile thing to deliberately acknowledge, exploit, market to and goad on that subset. Or to trivialise it.
My feeling is that so long as it fits the concept well, that it has artistic merit and isn't exploitative, it's fine.
Trent's been very open and communicative about himself in the past, and has proven to very definitely not be the kind of person to prey on damaged people. But it's a fine line to tread, and I hope the concept comfortably justifies the title.