Помогите перевести фразу с английского (знатоки языка, не гуглопереводчики)

The
overthrow of some social convention for an ideal would, does not come
within the scope of its doctrine and therefore the theory that every
man benefits himself most as he helps his fellows falls to pieces.Как-то не получается понять целиком всю фразу.. . возможно дело ещё и в запятой между would и does, поставленной возможно неверно, но всё-таки.. . "...и поэтому теория, что каждый человек больше выигрывает, когда помогает своим, распадается на части. "

Вот контекст:

But the thesis breaks down when a man's happiness is supposed to the good
of the community. A man who is to be hanged for the good of society,
if offered a chance to escape, will not argue that it is for his own
advantage to be hanged because it is good for the rest of the world.
Even apart from the powerful motive of self-interest in such a case,
the only morality this philosophy has to offer is of a mean and timid
nature. The argument is operative against generous and heroic action.
The overthrow of some social convention for an ideal would, does not
come within the scope of its doctrine and therefore the theory that
every man benefits himself most as he helps his fellows falls to
pieces. Yet the theory still hangs in the air.

Речь идёт об утилитарной теории, а точнее о её тезисе о том, что счастье индивидуума равно счастью общества.
(

self-interest
is identical with the interest of the community, contending that what
is best for the individual is best for society at large
)