In the early years Warhammer 40k was satire on conservatives, Marget Thatcher,

We can add to that Priestley’s lived experience in mid 20th century Britain; the long-tail of the Second World War and the end of British Empire; the ongoing civil discontent of the '70s and '80s between trade unions and the government; the UK’s ongoing military operations in Northern Ireland; state sanctioned support for the South African Apartheid government; and the Falklands war. All fed into an early 40k corpus that was politically charged and anti-authoritarian.

Even so, the game’s general message was typical of most punk pop culture of the period: authorities are oppressive, corrupt, and bureaucratic; advanced warfare is still barbaric; systems of oppression inevitably create the rebellions that they use to justify themselves; and so on.

https://www.wargamer.com/warhammer-40k/satire

From the very beginning, Warhammer 40,000 wasn’t a straight military setting. It was a joke; a loud, gaudy, aggressively unsubtle joke told by people who were deeply suspicious of power and perfectly willing to mock it. The early writers weren’t trying to smuggle politics into a neutral universe; they were holding up a funhouse mirror to the authoritarian impulses of the late twentieth century and exaggerating them until they became grotesque. The Imperium wasn’t designed to be admired. It was designed to be too much; too cruel, too bureaucratic, too pious, too militarised. A warning dressed up as a wargame.

The satire was everywhere. The Imperium’s bureaucracy was so swollen it became a character in its own right, a kind of cosmic Civil Service (perhaps a DMV for our American cousins?) with skulls glued to it. The Inquisition was a parody of purity culture, a machine that valued suspicion over truth and zeal over competence. Space Marines were propaganda posters made flesh, the state’s ideal soldier stripped of humanity and sold back to the public as salvation. Even the tagline: “In the grim darkness of the far future, there is only war”. This wasn’t a mission statement. It was a punchline. A bleak little wink that said: this is what happens when a society builds itself entirely around fear and obedience.

https://norerolls.co.uk/2026/02/03/the-strange-half-life-of-politics-and-satire-in-warhammer-40000/

Rogue Trader which it was based on was a parody yes had a lot of references to politicians or political doctrine at the time. It evolved over the editions as it gained popularity, especially outside the UK. The parody now is much darker in tone, less comedic or silly. The problem is they started to realize how cool the setting was as they developed it and took out even more of that satirical bite. There’s some satire still but it’s not as on the nose now.

I’m not too familiar either, but didn’t it rise to popularity shortly after decolonization?