Yes, the point is that it's often unsafe to eat a food item that has gone mouldy, even after removing the visibly mouldy bits.

The implication of the "people used to die for no reason" line is that 'we always did x in the old days' isn't necessarily a good argument for the safety of x. The link between action and consequence is often obscure, especially for the class of actions that usually turn out fine.

This is from the article:

> Purrington, meanwhile, has reflected on his Twinkie experience. While his father had no objection to eating moldy foods, he recalls, his mother generally treated "sell-by" dates with more respect.

So I assume the top-level comment is a confirming anecdote.

The article also says that he thought the Twinkie looked fine before he ate it. So it seems that by checking how it looked and ignoring the age of the product he was in the middle-ground between his mother (respect the sell-by date) and his father (happy to eat moldy foods) :)