Isn't Meredith's "anti-corruption" position more like the Chinese purge of rivals than any genuine anti-corruption campaign?
There's no sign that I can recall that she's going after templars who commit abuses against mages and at the least indications that her own use of tranquillity goes further than Chantry law intended.
Not really. Until Act 3 (which is when she's already insane), Meredith's anti-corruption is across the board. Templar abusers like what's-his-face (alrik?) have to hide illegal Tranqilization, NPCs lament that that it's no longer as easy to bribe templars as it used to be, and Meredith even makes high-risk attempts on noble-related apostates, such as Dupis (or however it was spelled- the blood mage suspect for the serial killer).
Meredith's power is limited and so she has to pick her battles- she doesn't have enough to go after Hawke directly in Act 2, when he's got the Viscount's favor- but she doesn't pick her battles on the basis of protecting friends either. There is no Meredith-ignorred cabal that she permits because it's politically allied. Accusations of Templar corruption we investigate in Act 2 are consistently unsanctioned, or forbidden by Meredith (such as the Tranquil solution). Alrik even has to blackmail fellow Templars when going after Anders. Meredith goes after her rivals because she sees what they're doing as wrong (such as the lyrium smuggling), not because she's not getting a cut.
The distinction with the Chinese purge is that Meredith isn't purging rivals but leaving allies complicit in the same things alone. Through Act 2, she's not sanctioning illegal tranquility at all. Come Act 3, when she is insane and is, she's not prosecuting Templars for doing the same.
Orlais seems utterly corrupt. So does Orzammar. Fereldan has relatively low power disparities. It doesn't seem like a bastion of justice either, but the clearest cases of injustice we see are against the Elves, who are most powerless people of Fereldan.
The only place that might not be massively corrupt are the Qunari, which is supposed to be a very equal society. Though I'd argue that any sort of real Qunari state would be both massively unequal and massively corrupt.
Of course this fits in well with our own history. Corruption was historically ubiquitous until very recently.
Indeed it was, and still is- which is why the 'it's okay for me to be corrupt if the society is corrupt' angle can often come off as culturally chauvenist. It justifies continuing inflicting a social harm on a lesser society, rationalizes hypocrisy on who the law applies to, and rests on familiar fallacies such as demanding perfection in exchange for, well, not doing what they condemn others of.
One of the more interesting defenses I heard from a man who took bribes from Westerners when he was accused of corruption was 'I'm corrupt? You're the ones paying me.'
Condemning a group for being corrupt when you're an active participant makes claims that your corruption is alright just a form of special pleading. The moment you begin 'my corruption is morally acceptable because-', you've lost position to condemn corruption in general because you're already conceding it's a matter of context, not objectively bad. At which point, your argument becomes subjective and unsustainable. What sort of reasons (and who gets to decide them?) for deciding when the law shouldn't apply? And why does that even matter?
What, for example, does Kirkwall being corrupt have to do with Anders being willing to murder a mage who's afraid of him? How un-corrupt does a city have to be so that we should expect would-be murderers to be turned in as menaces to the public?