Corporations are inherently the vehicle of non-mutually-beneficial capitalist profit-seeking. They cannot really be anything else. That's what differentiates them from e.g. a profitable 'mom-and-pop' grocer.

The purpose of incorporating as a business is to limit liability by separating the assets and incomes from the owners and investors, in order to allow profits to be gained without actually engaging in a good-faith exchange with prospective business partners/customers (since corporate bankruptcy limits their ability to recoup losses from the individuals running the business).

Weapons are a means to do harm, but they are not something that the mere ownership of implies a threat from; most people do not being their guns everywhere. If they do bring it somewhere, that indicates an adversarial stance towards the place or persons who they're meeting. Put another way, "gun ownership" is very different than "having a gun present at all times with which you could threaten someone".

Corporations, on the other hand, are at all times and in all business dealings leveling that threat of one-sided liability/risk, because it is intrinsic to them as corporations. You can own a gun without threatening to shoot anyone with it. You can't operate a corporation without threatening to evade rightful liability.

So it's possible to be a "responsible assault rifle owner", but it's not possible to be a non-exploitative corporation.