The distinction exists for a reason, but that reason doesn't in itself require taxation to happen twice. If I am in business I can pay tax once or, as the owner of a corporation, potentially pay tax twice. I will obviously prefer the former.

Since, as you say, the corporation is legally distinct, whether I own the whole corporation or just part of it is neither here nor there. My objection is the same, which is that there are two tollgates between me and what I see as my share of the income.

Australia's corporate tax system allows for "franking credits". Shareholders receive these from companies based on their proportional ownership. The income tax paid by the corporation may be offset against the income tax owed by shareholders.

Unsurprisingly, Australian companies are much more likely to pay dividends.