No willful ignorance is not an excuse.
JWs have access to all the same information we have access to, they don't even have to look at apostate sites for information if that would be too disturbing to their delicate sensibilities.
I don't see ignorance as the problem anyway it's a symptom, a symptom of the thought stopping that comes with indoctrination. Repeated indoctrination instills fear, disables the conscience and rational, logical thought processes go out the window. If reasoning ability and conscience were intact it would prompt them to research.
Until a JW sees, thinks or feels something is very wrong with their religion they are not likely to research.