Stiles didn't know a lot of details about Panem, but given what little he gleaned from Finnick, he knew it wasn't a pleasant place. Johanna's hesitancy to get into details, along with the fact that they didn't get to spend more than a few weeks a year together, were further hints that there was a lot of darkness in their world. As someone from Beacon Hills, which seemed to have non-stop darkness, Stiles could understand why they might be reluctant to discuss the specifics.
"Speaking as someone on the other side of that issue, it's weird as hell," he admitted. "I mean, there's part of me that wants to know everything. But another part of me is afraid to know. And it's hard because I feel like there's this... unspoken pressure for our relationship to be what she remembers it being."
And it wasn't that he was completely opposed to the idea of having a more intimate relationship with Malia. He just didn't like the expectation of it. Especially since it seemed like he was inadvertently hurting Malia in the process.