Please note that I wrote "respectably
dressed families". I did not write "respectable family".
My father grew up at a time when gentlemen wore jackets, ties, and hats when frequenting expensive establishments. Dressing appropriately was considered a sign a respect.
We live in a time when some people go to their places of worship in t-shirts and shorts.
Jiko actually has a dress code. Quoting from the WDW website:
At this Signature Dining experience, Guests are asked to adhere to the dress code.
Men may wear khakis, slacks, jeans or dress shorts and collared shirts. Sport coats are optional.
Women may wear capri pants, skirts, dresses, jeans or dress shorts.
Not permitted in the dining room are tank tops, swimsuits, swimsuit cover-ups, hats for gentlemen, cut-offs, torn clothing and shirts with offensive language or graphics.
A "respectably dressed family" dresses appropriately for their environment.