What do you think american writer, politician, and actor will rogers meant when he said, “there is nothing so stupid as the educated man if you get him talking about something he wasn’t educated in.”

Will Rogers meant pointed that we all are ignorant but in different fields. If we take that thought about Rogers and read the given excerpt, we'll see that it makes totally sense.

Rogers often said, that educations is the only weapon that can kill movies, that is, leisure is the enemy of education, it makes people more ignorant. However, even "educated" people are ignorants in some way, because it's impossible to know about everything, it's just not possible, and this can be demonstrated, if you take a lawyer, and put him into a health situation, we will be seen as the most ignorant person in the world, because he's an expert in laws, but not in diagnosing people, and curing them

a lot ig i am not sure