So-called propagandist’s excessively outspoken lines about Kennedy on vacation (5,4)

'so-called propagandist's' is the definition.
I don't know anything about this answer so I cannot tell whether this works.

'excessively outspoken lines about kennedy on vacation' is the wordplay.
'excessively' becomes 'too' (synonyms).
'outspoken lines' becomes 'rose' (I can't explain this - if you can you should give a lot more credence to this answer).
'about' indicates putting letters inside.
'on vacation' says to hollow out the word (remove centre letters).
'kennedy' with its middle taken out is 'ky'.
'too'+'rose'='toorose'
'toorose' placed around 'ky' is 'TOKYO ROSE'.