Your link requires a login, so I can't be 100% sure, but I believe you have found an error in the web site's text. The site should have used the verb "are."
But there are other issues with the sentence, too.
But, most concerning of all, the advice given in the sentence is incorrect.
Grammatically, adjective order does not imply a closer or more relevant association with the modified noun. For example:
The large, red ball rolled down the hill.
The red, large ball rolled down the hill.
In written English, these two sentences are equivalent. The ball is both large and red (or red and large, it doesn't matter). In spoken English, the speaker may choose to emphasize the closest adjective by vocally stressing the word, giving it greater weight or importance compared to the other adjectives.
However, the behavior of stressing the adjective closest to the noun (I hesitate to call it a rule) is one of spoken convenience. Vocally stressing the outermost adjective would be legitimate, but it would sound wrong to most native listeners because our habit is to stress the closest adjective.
But, to repeat myself, this is not a rule and therefore does not translate to an order of precedence (in written or spoken English). In written English, a word is given greater weight or importance though the use of italics or another visual emphasis.
The large, red ball rolled down the hill.
The red, large ball rolled down the hill.
Finally, it should be noted that adjectives describing a physical property of an object (size, weight, volume, etc.) are generally listed first. Thus, the first example in each pair will likely be the most comfortable to read by native English speakers.
EDIT
Eddie Kal provided a link to the BBC blog that contains the phrase the OP is asking about. The respondant, Catherine, did a fantastic job of explaining the nature of adjective order, but that doesn't excuse her for the messy sentence the OP asked about. Ugh.
What she meant by her statement is this:
Adjectives that describe a permanent or intrinsic aspect of the noun are listed closer to the noun than those that describe a temporary or circumstantial aspect of the noun.
Catherine's example is a "comfortable wooden chair." The chair is made of wood. That cannot change. It is an intrinsic fact of the chair's existence. However, the chair's comfort can be affected. As it gets older it may develop splinters, or if left in the rain it may be wet, both conditions resulting in an uncomfortable chair. The comfort of the chair is a circumstantial condition, and is therefore listed before the intrisic wooden nature of the chair.