Just because it is too in line with the public's aesthetics? From a historical point of view, we may be real. We are all ordinary people, and naturally we like to read the calligraphy that we think looks good. Those well-behaved calligraphy are more popular with us.
Throughout the ages, calligraphers' calligraphy customs have been criticized, and calligraphy looks not elegant enough.
Sometimes people say "vulgar books" are not ordinary people who write calligraphy, but masters whose calligraphy is recognized as powerful and has always been known to our descendants. First of all, we all know Wang Xizhi, a "book saint". Han Yu also wrote a poem saying that Wang Xizhi's calligraphy was vulgar. Wang Xizhi is still like this, and other people's calligraphy will be called vulgar.
Similarly, now everyone practices calligraphy, and many people love to practice Liu's body. Liu's body is very good, but as the pioneer of fluid, Liu Gongquan, many people will also say that his calligraphy is vulgar. There is no uniform standard, and it is judged by personal feelings. Maybe it's right, maybe it's just personal will.
So sometimes it will appear, even if this herringbone is well written, but when you meet a person who doesn't like his handwriting, he will still think his handwriting is vulgar. This is based on personal feelings. There is no uniform restriction.
Of course, sometimes we comment on whose calligraphy is elegant or vulgar, and also combine our own personal reasons. For example, everyone knows Qin Gui, although his handwriting is very good. But we always try not to mention him. Because his character is not good, even if his handwriting is good, it is a "vulgar book" in our opinion.