I'm not sure Sam Neill knows what 'terrorism' means

Of course I love Sam Neill, the great New Zealand film actor. 

But this tweet has me baffled:

'Terrorist' is not a catch-all term for anyone who commits a heinous act of mass violence. It carries a specific meaning that relates to the motive behind the violence. 

The Oxford English Dictionary defines a terrorist as:

A person who uses violent and intimidating methods in the pursuit of political aims; esp. a member of a clandestine or expatriate organization aiming to coerce an established government by acts of violence against it or its subjects.

Neill seems to think that the reason Germanwings co-pilot, Andreas Lubitz, is not being called a terrorist is because he is European; and that the (alleged) presence of mental illness is considered an exculpatory factor for a European when it would not be for someone of another ethnicity.

To the extent Neill is saying that many people might quickly deem this a terrorist act if the perpetrator were Muslim, whether or not the individual had a mental disorder, he has a valid point. (Although, we have very recent case in point, MH370, where early rumours of terrorism on the part of Muslim pilots and crew did not withstand the absence of evidence of political or religious motive).  Without any proof, people are wrong, and undeniably bigoted, to assume every crime committed by Muslim is terrorism – just as Neill is wrong, based on what we know so far, to call Lubitz a terrorist.

I am not sure what Neill is really advocating here. Is he saying that, because some people – horrible white oppressors – are too quick to apply the term "terrorist" to Muslims, we should misattribute the term to non-Muslims as well?

A better principle might be to use the word accurately in all instances.