Yes, when your job is to be a neutral arbiter of a very narrow legal compliance issue.
It is not his job to be prejudiced about the company as a whole, to conduct arbitrary investigations, or to punish the company by interfering with the work of its executive team.
His job is not to be a neutral arbiter, indeed, the very definition of his job is that he not be neutral. His job is to monitor compliance.
The easiest way to do this would be to periodically interview those responsible for implementing compliance. The alternative would be for him to audit (i.e., investigate) Apple's relevant business and operational activities, which would cause a significantly greater disruption to the business.
His job is absolutely to monitor compliance, but it is not his job to punish the company, investigate it for anything else, or to harrass the executives. If he cannot monitor for technical compliance without assuming an overreaching authority over operations, then a more competent monitor should be assigned.
His job is not to be a "neutral arbiter." The court appointed him not just to passively monitor compliance, but oversee Apple's revising its policies and employee training to address the compliance defect. This job obviously involves some level of investigation and working with and directing the executive team. It's entirely Apple's characterization to say the investigations are "arbitrary" or that he's "interfering."
A large company like Apple has policies and training in place to ensure that lower-level executives and employees don't violate the law in the course of their jobs. In the antitrust context, executives and employees responsible for purchasing or interacting with competitors must be trained to know what kinds of communications are legal, and what kinds of communications amount to collusion or price fixing.
Bromwich's job is not to passively monitor the kinds of deals Apple enters into. Instead, the court ordered Bromwich to help restructure Apple's internal antitrust policies. Like any major internal policies, they are promulgated and implemented by the high level executives. That's why those interviews are necessary.
Sure, but he needs to be able to do this without interfering with the rest of the business, very little of which has to do with ebooks or even content deals. If he can't do that, he is the wrong person for the job.
That he's "interfering" is entirely Apple's version of what's happening. All we know is that he's tried to schedule meetings with Tim Cook, etc, which is entirely appropriate in an internal investigation and can certainly be done without "interfering" with the rest of the business.
Lying would be if Apple said that Bromwich demanded daily two-hour meetings with Tim Cook when he in fact had not. Saying that Bromwich is "interfering" is merely characterization. One man's "interfering" is another man's "getting an executive to spend time on an issue he doesn't want to deal with, but which he is obligated to do so." You shouldn't take a characterization at face value, not when it's made by an interested party.
It is not his job to be prejudiced about the company as a whole, to conduct arbitrary investigations, or to punish the company by interfering with the work of its executive team.