I would think that people then responded like me and many others do today when we hear the Buddha's message with an open mind; that is joy knowing that there is a path away from suffering and toward serenity and peace.
Theravada Buddhists
Help the people to follow the law.
henry the 3rd
follow a code of moral conduct
People who believe in and/or follow the teachings of the Buddha can be found throughout the world. In some Asian countries it is the main "religious" belief. In North America and Europe many of the population incorporate Buddhist teaching and thought into their daily life although they are not Buddhists.
French people follow the Christian, Jewish, Muslim, Buddhist, and other faiths. Some French also are unaffiliated.
The people living in Timbuktu primarily follow the Islamic religion.
The laity of any religion refers to the people who follow the religion who are not clergymen. In Buddhism, the laity are the people who practice the religion, but are not leaders of worship.
For similar reasons that other people follow the Christian religion, the Islamic religion, etc. - basically, because the believe in it.
During the period of disunion, people took comfort in the Buddhist teaching that people can escape suffering and achieve a state of peace.
I think by definition a 'Buddhist person' is someone who follows the teachings of Buddha. So yes I think all Buddhist people follow Buddhism to a greater or lesser extent.
In terms of statistics and percentage, Mongolia has the highest Buddhist population, because 98% of people who live in Mongolia follow Buddhism. But Mongolia is sparsely populated, so in terms of actual figures, the highest Buddhist population is in China, the most populated country in the world. It is estimated that anywhere from 277,588,896 to 1,057,481,510 people in China follow Buddhism.
Because teaching that people are equal is quite different from teaching that religions are equal.(And some religions actually do not teach either of these things!)