As students, we know that it is sometimes hard to make it to class due to physical and/or mental health problems, or other aspects of a student's personal life.
It is common for students to complain about attendance policies and excused absences because not everyone can get a doctor's note for every issue that they are facing throughout the academic year. My roommate recently brought up how her professor opened up a discussion in their class regarding this topic - he recognized that this is a common problem that he sees on campus and that there needs to be more understanding in that aspect of our education system.
Some students need to support themselves financially and have rather hectic schedules which causes them to face more stress than some of their peers. There are also many who have chronic conditions that are not directly visible and are at times uncomfortable to discuss with a professor/teacher.
For example, every girl faces menstruation each month but some of them have many complications regarding it involving fainting spells and intense pain. How is this fair to count against female students and expect them to meet an attendance requirement when male students do not have to deal with these problems? This is, of course, an issue regarding specifically female students, but it goes to show that one student cannot be compared to another based on attendance when there are various factors that affect a person on a daily basis.
There are definitely students who take advantage of professors who have lenient attendance policies, but they are ultimately wasting their own time and money if they perform poorly on assignments and assessments. So is it fair to penalize students who actually cannot attend classes? Attendance tends to be a small percentage of a student's overall grade at the end of the semester, but this is often what "curves" a student to receive a desired grade, especially in a class in which a professor does not round grades up. At the end of the day, teachers are responsible for teaching material and students are responsible for learning it and catching up with work they missed.