It all depends on your perspective on the issue.
If you're a restaurant operator,your goal is to maximize your business profit.And,if the food you serve is very popular,you would certainly hope you will serve more customers.Therefore,it's totally fair that you would try anything to cut down the time customers linger on after finishing their meals.It makes business sense.
From a customer's point of view,it further depends on which side you're on.Assuming you are one who's still waiting to be seated,you would probably wish for those who have already finished eating to get up and leave - so you can take their place and enjoy the delicious food.Yes,that's the reason you go there in the first place - the food.And,no,you wouldn't think it's a bit unfair.
So,unless you're someone who would spend an entire afternoon or evening in a restaurant after you finish your meal,you couldn't care less if the eating place is comfortable or not - so long as their food is worth it.
No,I do not think there is any merit in casting opinion on this issue.