The typical picture you have of a political reading is somebody reads a poem by Basho about crickets chirping or something and then tells you that it's about the anxiety of Edo period japan about colonialism. In this case, I think you can make a non-cynical argument that this is a limiting way to read the poem, and you might be better off with some close analysis or whatever.

In the general case, especially in the specific case of novels, it's absurd. Novels were born in broadsheet newspapers - the original texts for many of the stand-outs of the genre were published in serial format, right next to adverts for soap and opinion columns. The names he invokes kind of damn his argument rather than support it: George Eliot edited a left wing magazine, Emily Dickinson was published in the Springfield Republican, and so on. I was honestly surprised to find out that Austen was self published: a big point of episotlary novels is that they can be published letter-by-letter in a weekly paper.

Doestoevsky was famous for loving newspapers - not because that's where his novels were published, but because that's where the live written culture of his time was. Bahktin said (iirc) that his novels were pure ideology, in the sense that the raw material of the work was woven from the rants, commonplaces, and opinions they were published side by side with.

Hemmingway is more or less operating at the opposite pole of the spectrum - and 'operating' is the key word here. He had a very specific idea about how to write, what language to use, that is very different than most novelists - part of that is obvious just in the way Hemmingway reads, but part of it is also implicit - while a really typical novelist like Dickens is obsessed with not just how people talk, but also why, what causes they are involved in, arguments they make, Hemmingway is writing much later, when novels were standalone things you didn't get in serial format, and you could make some kind of case for a transcendent, 'high art' novel.

Now, I thought it was cynical because this stuff is obvious to somebody like Bloom. He knows that to read your average novel while ignoring the political context is like listening to Bach and putting your fingers in your ears and going 'lalalala' every time you hit a religious bit. And, when you put Bloom in his political context, he's a man who got his first job in a couple of years after two americans were electrocuted to death for being communist spies, when academics everywhere were being frozen out for having the wrong politics, so you can really see why the incentives were there to go 'lalala' when you hit some of the racy political sections in your average 19th c. novel.

When it comes to varied or sloping terrain, I think it's totally possible to have a varied ideological terrain in a novel. In fact, I think it's unavoidable. I think that's absolutely a good principle when reading novels: to pay attention to at which point they depart from the course set out by the author's various enlistments. That's different to saying a novel is not 'ideolgical' - it's saying a novel is composed of many different and often contradictory ideologies. I think this is definitely a reasonable approach, if you imagine the novel placed right in the middle of a lively comment section of a tabloid.