Again, my interpretation, but the minister is not calling for Czech WW2 veterans to be given British benefits.
All he is saying is that you cannot judge a person's value to a country based on the number of years they have lived there. He is using the example of the Czech pilots who helped to defend Britain from the Nazis to make this point - no one calls into question their value to our society, yet they were here for less than 4 years (the proposed cut-off point for EU nationals to receive benefits in the UK).