Everyone talks about how Gaban’s words might be about Sanji rejecting his Germa roots, but that’s bs to me. And him being scared of himself is an idea I believed in, but it looks like that ship has sailed.
At this point, I think it’s more likely this fucker Judge, along with his sons, simply destroyed Sanji’s self-esteem to the point he believes he could never be good enough. That idea is ingrained in him because that’s how he’s been treated for a big part of his childhood. This kind of childhood trauma doesn’t go away easily.