First of all, public goods have the characteristic of being both non-excludable and non-rivalrous, so that means that every citizen has the right to use a public good, or in other words that person can not be excluded from the use of the good and that the use from another citizen does not prevents simultaneous consumption by other consumers.
Second of all, the government must provide these kind of goods because it is their duty to make sure that the people and only them are the most importance thing to take care about, so that means that there is no personal or private interest involved in the creation and divulgation of public goods. Moreover, it is important to understand that the government does not seek for profits but it does for the common good of the majority, instead of the private companies that are more interest in making greater amounts of money.
