I am from the town. I am seeing these posts every day.
I think the reason LH is having these threats is because of what happened to her afterwards. He is being seen in the same light as SB and even though he isn't charged for her murder, LH is being called a murderer.
I wouldn't say I feel sorry for him as he should be charged with the crimes he committed. However, I think the reaction is what it is due to the awful outcome.
LH was very social, you saw him about a lot. SB not so much. I wonder if this adds to the outrage. Most people of similar age went school with both. But the big difference is most people had seen LH recently - whether as a friend, just passing in the street or at the pub. Perhaps some had said "hello" to him not so long ago. That makes it hit home a lot more for people.
This is only my assumption. I was not friends with either men, but went school with both. If I ever bumped into LH though he'd always say hi. He seemed like a normal bloke, and that can make the reaction worse, I believe.