So what is "stealing?"
steal: verb. 1 [with object] take (another person's property) without permission or legal right and without intending to return it
By definition, since many of the condiments are free to take or are freely offered by some businesses, it is NOT stealing at those restaurants. Since the stuff is there to take, we have "permission."
Some businesses do not offer such things and therefore you have to pay for extra condiments. Taking those WOULD be stealing.
But what about morals/ethics?
Ethics: noun: a set of moral principles, especially ones relating to or affirming a specified group, field , or form of conduct
Morals: noun a person's standards of behavior or beliefs concerning what is and is not acceptable for them to do
So, is it not true that morals and ethics are ONLY set by and for oneself? Do they rightfully extend to others? Of course there are generally accepted morals (don't kill, don't cheat on your wife, etc…) but many moral issues are not defined by law as "legal" or "not legal." It's not against the law to commit adultery in some states. It's left up to the individual to decide whether THEY think it's right or wrong and deal with any consequences that may arise out of certain conduct. Be it cheating on your spouse or taking an extra packet of ketchup. (I know, those two things are very similar.)
Me? If I make a purchase at a restaurant and there are some "free" condiments sitting on a table, I have no qualms about taking a FEW things. However, I'm not going to go to McD's ONLY to take condiments, nor will I take an exorbitant amount of them. Taking a few condiments is not against the federal, state, or certain restaurant's laws. However, taking a few extras MAY be against an individual's morals. These are two very different things.
Boy, kinda ridiculous for some ketchup packets, huh? :D