I can see why you want to 'blame' something. I do agree with PP that your DS would be much worse if you weren't so gentle.

DS was born via emergency c/section and due to breathing problems was in a humidicrib for 12 hrs... I got to hold his hand for about an hour (cause it was midnight) but didn't cuddle or feed him until he was over 12 hrs old. I am still bf and while DS starts off the night in his own bed we co-sleep from the first wakeup and feed a few times overnight still. So while I wouldn't say I parent exactly the same as you did for L I do feel it is similar to how you parent. DS is a very social and independant child (we don't go to playgroup and he has never been in childcare) I think his personality has as much to do with it as my parenting.

No words of wisdom on how to guide your sensitive boy but hope the options already suggested help.