When I finished Episode 1 for the first time, I was worried that Larry would try to use Lee's past against him with the whole group, just like how Lilly does after you decide to abandon her or not. He also threatened to do it in the meat locker.
Originally Posted by Jaded X Gamer
Probably because Larry didn't know how the group would respond to that news. There's no guarantee the others would turn on Lee and considering how "popular" Larry was with everyone else it's quite possible it may have backfired and turned people against him. That's probably why he tried to kill Lee when he did, he saw an opportunity to get rid of him while most of the group was distracted.
The fact that Larry tried to kill Lee is probably another reason he was keeping it to himself. I doubt Lee wouldn't throw that back at Larry if he outed him and Clementine saw it happen so it wouldn't be just Lee's word against Larry. Depending on how Lee's acted that may actually make Larry look like a bigger risk to the group if he's willing to make such snap decisions.
"Hey, I'm not the bad guy. This guy (who risked his life to get pills that saved my life and may have done similar heroic actions for the rest of you) is a murderer. So I had to murder him first, just like when Duck was bitten..."
Lilly would obviously take Larry's side but that's about it. I doubt Clementine would approve of kicking Lee out of the group and she's pretty good at guilt tripping people. (She manages to changes Christa's mind about Ben in Crawford.) Kenny would probably depend on how you treated him, but with Katjaa and Duck around it's doubtful he act to rashly and if Lee had sided with him he probably come to Lee's defense against Larry, the same guy who wanted to throw Kenny's son out. Both Carley and Doug end up owing their life to Lee and in Carley's case she already knew about Lee's past.
Holding onto Lee's secret gave Larry a bit of leverage over Lee, which he probably figured would keep Lee in line. He spills the beans it takes that advantage away and what happens to Lee depends on the group and there's no guarantee the group would side with Larry over Lee, especially considering the way Larry has acted to everyone.
I could actually picture Larry saying something like that if things worked out differently in Episode 2 and he survived. Since I've been Kenny's pal and agreed with Carley about telling my past to others, they'd both come to my defense against Larry. Clementine too. Maybe Ben, but I don't know. I could also picture Lee saying, "Seems like it does
pay off to have people you can trust by your side and not be a total dipshit to everybody, now does it, Larry?"