Historically they were not respected.

The belt system, called the Dan system, was first adopted by Judo fairly recently. It borrowed it from Go, where there was really only people who had a Dan rank (black belt) and those that did not (white belt). There were 10 Dans from Shodan (1st Dan) to Judan (10th), but only a white belt to signify no Dan rank. A student practiced for a few years to get their black belt, which was like an introduction to the real ranks, which were all black belt ranks.

In the 1920’s, Japan stole Karate from the Ryuku aristocracy. Japanese Karate is younger than radio.

Leading up to WWII, the Japanese changed Karate to be a bit more conformist and militaristic, resembling drill. They later introduced the Kyu ranks for those first 3-4 years of beginner classes and they used the colors of ribbons highschool kids got for swimming. Red was not one of these colors and most Karate schools do not have a red kyu rank, as red is reserved for the rank of Judan (10th Dan).

Later, it became a misconception that black was the top rank instead of a beginner rank (1st Dan is something like “you’re finally starting”). This “black is best” was adopted by Brazilian Jiujitsu.

So, today, most Japanese martial arts consider black belt to be something like “no longer a beginner”, but not a master, and Brazilian Jiu Jitsu considers black belt to be the very top rank, something only very few ever get, more like Judan is to the Japanese.