You are taking it out of context, though. BH is basically talking about an issue that could kill your startup. Whether or not you like that reality, there is a real risk that the other company will retaliate for something they see as an adverse breech of trust.
Note that logic: the problem is not with the company ben is advising. The issue is at the third part company. If that company decides to "go nuclear" and sever all ties because you poached/goaded or otherwise got involved in their "interal politics" (note: this is not a per-se issue of math/economics/money), bad things might happen to your firm.
CEOs of startups have a fiduciary duty to avoid "bad things", and even that choice is a catch-22 (ie, two bad things...) you pick the worst-bad one. And that is what he is saying.
In other words, he's talking about something that is a real-world problem. If you want to vent out about the issue, it really sits with the third part company. They are typically the one with all the power in the situation.
Example:
Startup A had 80% of its business tied to a single company, BigCo B. Like it or not, the CEO of startup A needs to avoid a situation where the CEO of BigCo B comes to the conclusion that he won't do business with A becaus of Politics (note: not economics).
Whether or not poaching is politically sensitive (or offensive) and/or warrants this type of "nuclear" response, is a function of many thing. But none of that is BH's responsibility in the larger world.
This dynamics is something that has played out for millenia from kings and queens and royal courts to how the predisent and Y combinator select their staff and senior leadership.
At a certain level of the game, its all about trust. And polticial power is essentially a combination of trust and goodwill. And its easy to disolve and can reak havok on any company of any size when systemically undermined. So you need to pay attention to it.
In other words, this is a much bigger issue. The tack of trying to shoot or lynch the messenger is sort of misplaced. Because the startup is the employer and may have a power asymmetry with a potential hire; but that startup is in itself subject to potential power assymetries at much higher levels.
(This goes for pissing off BOD members, VCs, and Key clients alike...maybe it suck/isn't fair...etc... but the reality is you need to pick your battes as a small company. And picking fights with the consituents you need to help you build your biz is ~dysfunctional and needs to be understood as such.)