Is there a more broadly applicable expression for "doth protest too much"?
Solution 1:
Well the phrase- 'Denial ain't just a river in Egypt' comes into my mind.
This phrase is often used as a humorous and witty response to a person who is in denial i.e, in short, is protesting too much about something which he/she may subconsciously know what's correct.
I think it resonates with the phrase- 'The lady doth protest too much' reasonably well provided your audience is familiar with the context of the quote.
Quote History : QuoteInvestigator.com
Solution 2:
"Talk is about what is lacking" suggests "empty vessels make the most noise", but again this is mostly aimed at an individual - and also carries implications of foolishness and ignorance.
The Glorious Leader sounds like they're practising doublespeak (from Orwell's doublethink). Something along the lines of “The past was alterable. The past never had been altered. Oceania was at war with Eastasia. Oceania had always been at war with Eastasia.”
The most broad interpretation comes under the heading of Political Framing, but I think that's probably too broad for the question asked.
Solution 3:
In 2017 Alternative Facts became an ironic term for official positions without hard factual basis, based on an interview response given by US counselor to the president Kellyanne Conway, though granted this term is not very applicable outside of American discourse.
Solution 4:
I would call this a propaganda facade. Propaganda is the spreading of ideas, information, or rumor for the purpose of helping or injuring an institution, a cause, or a person. A facade is a false or superficial appearance.
North Korea has long been famous for this. In 2012, a wrong turn by a press bus allowed a glimpse behind the facade. The Kim family's propaganda machine has long strove to maintain a public image of North Korea to the outside world that fits their own narrative. But, leaks of this nature show that their image is little more than a facade.