What's the meaning of "With all the subtlety of a bulldozer"?

Question

With all the subtlety of a bulldozer...

Subtlety means:

The quality that something has when it has been done in a clever or skilful way, with careful attention to small details.1 (subtle: not easy to notice or understand unless you pay careful attention)

And bulldozer is a rough, big thing. Is there any irony? Does the writer mean she did that with no degree of subtlety(and with slamming)? Could you please explain it to me?

The full text is:

I BECAME OBSESSED WITH bipolar disorder. We were required to write a research paper for Psychology and I chose it as my subject, then used the paper as an excuse to interrogate every neuroscientist and cognitive specialist at the university. I described Dad’s symptoms, attributing them not to my father but to a fictive uncle. Some of the symptoms fit perfectly; others did not. The professors told me that every case is different. “What you’re describing sounds more like schizophrenia,” one said. “Did your uncle ever get treatment?” “No,” I said. “He thinks doctors are part of a Government conspiracy.” “That does complicate things,” he said. With all the subtlety of a bulldozer I wrote my paper on the effect bipolarparents have on their children. It was accusative, brutal. I wrote that children of bipolar parents are hit with double risk factors: first, because they are genetically predisposed to mood disorders, and second, because of the stressful environment and poor parenting of parents with such disorders.

Educated by Tara Westover

Answer 1

"Is there any irony"

The whole point of the simile is irony! It means "without any subtlety at all."

She had been pretending that she had a bipolar uncle, not a bipolar father. But Tara wrote her paper on "The effect bipolar parent have on their children" This is obviously (and without subtlety) about her own experiences with her father, and rather than being written in a scientific way it is "accusative and brutal". She uses her psychology paper to verbally attack her father.

Answer 2

With all the subtlety of a bulldozer...

Zero subtlety. None. Nada. Nix. Not any.

Bulldozers, as you point out, are not known for their subtlety.
They are big, heavy, blundering things that push anything in their path out of the way.