All the accepted notions and prejudices about flesh being pink.
There is no such expression as 慨世観念. I guess the author mixed it up with 既成概念（きせいがいねん）or 固定概念（こていがいねん）.
慨世（がいせい）alone means “to be furious about the recent bad trend in the world/society”. See also:
The Kanji 慨, meaning “to weep and hate”, is also frequently used as in 憤慨する（ふんがいする）, which means “get very angry”.
既成（きせい）of 既成概念 means “to be already formed/established”. So, 既成概念 is a common perception.
固定（こてい）of 固定概念 means “to be fixed”. So, 固定概念 is closer to “prejudices held by someone or a society for a long time”