You raise a number of issues worthy of consideration. I will make three points that might be helpful.
1. Genuine forgiveness, even when practiced frequently and for small issues, is legitimate because forgiveness is centered on the good. To forgive is the practice of goodness and everyone should be free to decide when and if they will forgive. So, this really is the choice of your friends.
2. You seem to be concerned with what we call false forgiveness. In this case, false forgiveness takes the form of dominance or power over others. If a person wants such power, he or she can feign hurt, openly forgive the other person, and continually remind him or her of the need to be forgiven. This is not helpful to anyone because it is not a true form of forgiveness and, depending on the situation, might incorporate control over others.
3. Practicing genuine forgiveness for the little things of life can increase practice of this difficult-to-master virtue. Thus, forgiving for the little things can be growth producing. Please see our Adult Forum discussion of these “little things” and forgiveness in our Forum section.
Now, it seems to me that your frustration regards point 2 above, the false form of forgiveness. A psychiatrist, Dr. Hunter, in an early article on the psychology of forgiveness published in 1978, made the point that most of us can identify the false form of forgiveness because there is a “smug” quality to the “forgiver.” I am suspecting that you see that in your friends. If so, you can help them by pointing out the three issues above and gently discussing the fine points of each, without accusation or judgment. Include yourself in the discussion so that this is not a blaming session, but instead an educational opportunity.