Wiktionary
champagne socialist
n. (context pejorative English) A person who claims to adhere to socialist ideology but does not act appropriately.
Wikipedia
Champagne socialist
"Champagne socialist" is a pejorative political term originating in the United Kingdom. The phrase is used to describe self-identified socialists whose comfortable upper middle class lifestyles are perceived to be incompatible with their professed political convictions. Other phrases with the same implication include " Gucci socialist" and "salon socialist".