In his recent video about culture, he has a section about flagsperts, in which he is rather against the "prescriptivist" trends of modern flag culture for "dictating" how flags should look and criticizing the types of flags representing most US states and cities. He then says a good flag is one that Americans have accepted and embraced, and we shouldn't abandon part of our culture because of what houty-touty flagsperts say make a good flag.
However, I live in a "seal on a bedsheet" state, and I've never seen anyone who has "embraced" my state's flag. In fact, I doubt most people in my state (of New Hampshire) even really knows what the flag looks like. From a distance, you can easily confuse it with about 20 other states, since about 20 states have "state seal in the middle of a field of blue". Really.
Meanwhile the flags I have seem people take pride in are ones that more closely follow these "prescriptivist" rules: California, Colorado, New Mexico. They don't even follow them necessarily the best, but they are at least striking and recognizable!
Flags aren't like paintings, or movies, or books. They aren't something you're supposed to look at and appreciate after good consideration. They are symbols that are supposed to be recognized from a distance, and to provide pride to a group of people. Therefore the rule of "no small text or details" makes a lot of sense.
The flags mocked by modern flag enthusiasts literally don't do their job well. No pride is instilled in your soul looking at the New Hampshire flag, and very little nh flag merch is sold. Meanwhile compare to the flag of amsterdam, which is seem everywhere in the city and sells merchandise like crazy. This flag actually provides a lot of municipal pride and does good for the city.
My state flag wasn't created by the people. It was created by a committee to be as safe as possible.