Speculating on how the "free hugs" sign came about:
I have a feeling that the "free hugs" sign originated in Devonte's habit of being inappropriately affectionate. I wonder if they maybe started doing it as a way of alerting people that their kid was prone to "giving hugs" to people they encountered out in public.
It might have been a way they were trying to channel his tendency into something a bit more controlled. They might have thought that it was cute or endearing for people to see a little kid with this sign around his neck when he came running over to strangers, rather than having to explain why he was doing it (due to history of abuse). They also might have tried to use it to help him learn to manage the behavior - turning it into a positive thing - telling him you can give "free hugs" - rather than just having him run up to anyone he encountered and grabbing on to them.
As he got older, the use of the "free hugs" sign morphed into something where he may have felt pressured to act in ways that maybe he was beginning to grow out of. The parents then also managed to find a way to channel this "free hugs" thing into their political activism and their need to maintain a certain persona on social media. So it took on a life of its own, and maybe Devonte was struggling with that, which would be normal for a teenager to start doing.
Since we don't know if they ever got any therapy for these kids, its hard to know if they were ever given any guidance about how to manage inappropriate affection due to attachment problems. I can almost imagine caregivers trying to deal with this type of behavior who have no guidance and doing something like a "free hugs" sign on the child's neck in public.
just some speculation....
And what about the free hugs project by ken nwadike?