Ignorant: 1. Destitute of knowledge or education. 2. Lacking knowledge or comprehension of the thing specified, resulting from or showing lack of knowledge or intelligence. 3. Unaware, uninformed.
For the purposes of this critique, it is the third definition for "stupid" that showing a lack of care, that will be relied upon.
You probably don't need to know that the corpus callosum, the cerebellum, and the temporal lobe are all components of the human brain. But if you're a neurosurgeon and you don't, you're not simply lacking knowledge or comprehension of the thing specified, in other words, "ignorant," you're also "stupid" in that you have shown a lack of care that will be relied upon.
You may not have much need to know the principles within the Bernoulli Effect, or the principles behind liquefaction, unless you're a civil engineer designing a bridge over a waterway. In that case, you're ignorant and stupid in that you lack knowledge and comprehension of the thing specified, and you lack care for that which will be relied upon.
You may not have an essential reason to research the genuine biography of a particular person; say an athlete, or a movie star, or even a political figure - their educational background, skills, record of accomplishments, and so on. But if that particular person is running for president of the United States and you're planning on voting for him or her, it seems to me you have an obligation to have on hand the necessary facts (not beliefs, facts) to buttress your decision. And if you haven't done at least minimal research for the basic facts (again, not mere beliefs, facts), then, by the subscribed to definitions, you're both ignorant and stupid.
Or, what would you call it?
Here are some of entire libraries-full very basic facts about John McCain:
The privileged son and grandson of 4-star admirals, with only a C+ overall high school GPA, he was admitted to the US Naval Academy. He graduated 894th in a class of 899. The fact he graduated, rather than being kicked out for academic performance and personal deportment, is once again traceable to his genetic lineage.
Not by dint of any personal accomplishment, following graduation he secured the plum assignment: jets. Regardless how he came by "jets," he managed to crash two of them and one propeller-driven trainer.
By his own admission, he resigned his Navy commission because his record was so poor, even allowing for his 5½ years of POW captivity, that he had "no future" in the service. It wasn't until he happened upon his second wife, Cindy Hensley (more in a moment) and, through her father's extraordinary financial reach of contacts, that he entertained moving to Arizona and entering politics! He has earned no education, began no business, entered no political fray, nor owned a home on the least of his own efforts.
Prior to the sea-duty deployment that ended in his being shot down over Hanoi, John McCain married Carol Shepp, an 18-year-old swimsuit model; fourteen years his junior! Christmas Eve, 1969, his young wife hit a patch of ice and a tree that left her needing 23 surgeries over a two year period, 4 inches shorter, and no longer quite as pretty; medical care paid that was for by Ross Perot, by the way.
As immediately as he returned, finding Carol no longer the ravishing young thing he had married, McCain began chasing a number of fresh young things, among which was multimillionaire Cindy Hensley; like Carol, an attractive blond, but one with money, and this time, a pretty little thing 28 years his junior!
In Worth the Fighting For, McCain wrote that he did not begin dating Hensley until he and Carol were legally separated. In his February 1980 divorce petition, under penalty of perjury, he swore that he and Carol were "cohabiting," which court and other documents prove conclusively was an abject lie. With the divorce petition court seal barely dry, he and Cindy married in April 1980, only five weeks later!