Socialist butterfly: A person who is politically active not through deep convictions, but as an adjunct or aid to their social life.
— The Urban Dictionary

Its natural habitat being, well, socialism:

“And then there’s the Butterfly,” Alice went on, after she had taken a good look at the insect with its head on fire, and had thought to herself, “I wonder if that’s the reason insects are so fond of flying into candles ― because they want to turn into Snap-dragon-flies!”
“Crawling at your feet,” said the Gnat (Alice drew her feet back in some alarm), “you may observe a Bread-and-Butterfly. Its wings are thin slices of Bread-and-butter, its body is a crust, and its head is a lump of sugar.”
“And what does it live on?”
“Weak tea with cream in it.”
A new difficulty came into Alice’s head. “Supposing it couldn’t find any?” she suggested.
“Then it would die, of course.”
“But that must happen very often,” Alice remarked thoughtfully.
“It always happens,” said the Gnat.

— Lewis Carroll, Through The Looking-Glass and What Alice Found There