Yes. Try ordering a side of bacon then covering it with your own couple slices of bread to simulate the taste of an actual sandwich (at one third of the cost) and see if you'll be allowed to hang around for three to six hours at any restaurant.
They provide bread under what most people understand to be the social contract: that you will order more than a side of bacon.
Some restaurants -- especially those that serve students -- even require a per-person minimum order to ensure that they're not losing money on cheapskates.
You, sir, are a cheapskate, in that you're willing to break the social contract as to further your own interests, while transferring the cost of your benefit to your host.
That someone can scheme up a rationalization for some behavior does not make it right, desirable, or honorable.
It's OK to put milk into a coffee you buy. It's not OK to buy one coffee and then drink several glasses of milk.
The same goes for seating. Seats and tables are there so people have a place to sit while they consume their purchases. There may be no set rule on how long it should take to you drink a coffee, but this is where people have to be honest with themselves and consider if they are really still finishing up that coffee or if they are now, so to speak, just drinking free milk.
If you want a cappuccino, buy a cappuccino. If you want a sandwich, buy a sandwich. Commerce is a collaboration between buyer and seller. Both sides are responsible for making sure that the value exchange is sustainable.