Wellington and the Portuguese government collaborated and enforced the evacuation to Lisbon. So, yes, Wellington is responsible for the ensuing mess among the displaced persons. If you order it and your troops assist in carrying out the policy, you own it.
And regarding the comment on the Royalist translator of Odeleben, I didn't say that made the book 'obviously thus unreliable.' I said that 'some care has to be taken.' There is a very large difference in what I posted and what you stated I posted.