explain this quote from chapter 5

Winston is talking about the periodical frenzy of nationalism displayed. Generaly the Proles go about their lives in general ignorance. They are not educated and are easily manipulated by the party if need be. The Party generally leaves them alone in their ignorance, they are not seen as a threat. Still, from time to time, the ignorant Proles get carried away in a fit of nationalism that they don't understand; the mood just seems to suit the occasion.