The word brigade, originally used to describe a military unit, can also be used as a pejorative

Pejorative

Pejoratives , including name slurs, are words or grammatical forms that connote negativity and express contempt or distaste. A term can be regarded as pejorative in some social groups but not in others, e.g., hacker is a term used for computer criminals as well as quick and clever computer experts...

 collective noun  to describe an informal group of like-minded individuals with views with which the speaker disagrees. It is used as a mild term of disapproval or contempt, or in an attempt to belittle and ridicule the subject.

For example, "PC brigade" is used to describe a supposed group of people who go around enforcing ridiculously politically correct

Political correctness

Political correctness is a term which denotes language, ideas, policies, and behavior seen as seeking to minimize social and institutional offense in occupational, gender, racial, cultural, sexual orientation, certain other religions, beliefs or ideologies, disability, and age-related contexts,...

 rules.

"Green welly brigade" refers in a deprecating way to well-heeled people who find their recreation in the countryside.

The 'Hang 'em and flog 'em brigade' is often used in British Politics to describe the far right who support a 'Daily Mail

Daily Mail

The Daily Mail is a British daily middle-market tabloid newspaper owned by the Daily Mail and General Trust. First published in 1896 by Lord Northcliffe, it is the United Kingdom's second biggest-selling daily newspaper after The Sun. Its sister paper The Mail on Sunday was launched in 1982...

' belief of capital punishment

Capital punishment

Capital punishment, the death penalty, or execution is the sentence of death upon a person by the state as a punishment for an offence. Crimes that can result in a death penalty are known as capital crimes or capital offences. The term capital originates from the Latin capitalis, literally...

, corporal punishment

Corporal punishment

Corporal punishment is a form of physical punishment that involves the deliberate infliction of pain as retribution for an offence, or for the purpose of disciplining or reforming a wrongdoer, or to deter attitudes or behaviour deemed unacceptable...

 and an end to fundamental human rights.

Similarly, blue rinse brigade

Blue rinse brigade

"Blue rinse brigade" is a somewhat pejorative term used, particularly in the United Kingdom, to describe elderly middle-class ladies usually of a conservative socio-political persuasion...

, morality

Morality

Morality is the differentiation among intentions, decisions, and actions between those that are good and bad . A moral code is a system of morality and a moral is any one practice or teaching within a moral code...

 brigade, NIMBY

NIMBY

NIMBY or Nimby is an acronym for the phrase "not in my back yard". The term is used pejoratively to describe opposition by residents to a proposal for a new development close to them. Opposing residents themselves are sometimes called Nimbies...

 brigade.

The term may have had its origins in The Angry Brigade

The Angry Brigade

The Angry Brigade was a small British militant group responsible for a series of bomb attacks in Britain between 1970 and 1972.-History:During the summer of 1968 there were a number of demonstrations in London against the American involvement in the Vietnam War, centred on the American Embassy in...

, a British anarchist group of the early 1970s.