How did "right-on" become pejorative in BrEng?

In The Guardian, I read the following passage

The former Leicester, Everton, Spurs and Barcelona striker, also vowed to continue to “speak up for refugees and immigrants and British values of tolerance and free speech”.

The [Daily Mail] article devotes 17 paragraphs to recounting what the rightwing newspaper calls Lineker’s “leftwing take on global politics” and “oh-so right-on views” before first mention of the 55-year-old presenter’s alleged tax affairs.

It seems that in British English, the expression "right-on" is used to mean:

(chiefly Britain, often pejorative) Possessing political and social views that are considered to be fashionable and left-wing.

However, how did this phrase come to have this meaning in the first place? IMO there doesn't appear to be such a clear link between the original expression "right-on" and this pejorative meaning.

Edit: Sources

  • https://en.wiktionary.org/wiki/right-on
  • https://www.collinsdictionary.com/dictionary/english/right-on
  • https://www.theguardian.com/football/2017/feb/09/gary-lineker-hits-back-at-daily-mail-over-tax-accusation

Solution 1:

WordReference.com has interesting discussion of a similar question about the meaning of "right-on". It appears that the compound adjective usage, with possible pejorative overtones, is predominately British: the Guardian article link in the post includes usage of “leftwing take on global politics” and “oh-so right-on views” referring to the same person.

How the British usage of the term may have come about seems clear enough. Left wing student type demonstrators, and hippies, in both the UK and Australia, after being exposed to the US idiom "right on" or "right on brother/sister" in film, television and music, adopted its use in their youth. Some of these will have continued to use the phrase in later life.

So it is hardly surprising "right-on" has come to mean a person with left wing or hippy-type values in some vernaculars, even if the person no longer uses the phrase to express total agreement.

It does, however, appear to be British usage and has not been adopted in Australia. Here the media tend to use "tree-hugger" (figuratively) in similar perjorative contexts.

Solution 2:

Per the Oxford English Dictionary (OED), in 1970 Time magazine had an article with

In Boston, Homans is known as a ‘right-on lawyer’—he defends blacks, war protestors and poor people.

Note all three groups mentioned are, generally speaking, connected (rightly or wrongly) with liberal politics.

Given that the expression right on meaning "enthusiastic approval" originated among African-American speakers of English (OED)–a group that, at large, is often connected with liberal politics (Cf Mr Obama), it seems the extended usage is obvious.

The OED's definition of the usage you ask about is

Admirable, worthy of approval. Hence: fashionable, ‘with it’, esp. in reflecting politically an approved liberal or radical stance. Sometimes mildly derogatory.

The usage is not necessarily pejorative. Presumably it is only pejorative when said in a pejorative manner.