Why are some clinics are like this ?

I’m not aware if a clinics are like this but every time someone gets to the office the staff always tells us any symptoms of COVID cough fever ext I tell them no. Well my daughter has been sick with a cough and stuffy nose she hasn’t been able to eat she only wants liquids well she has a doctor appointment for something else. She didn’t go to school as well. But I don’t understand how doctors office don’t allow children to get seen because they have a cough ? Not everything is related to COVID. Sometimes it’s the change of weather. Like how am i supposed to know what she had if they don’t allow sick patients in the doctors office