If that was the case then everything said would be a lie excluding universal truths. Universal truths are very common in mathematics but very rare in other areas such as psychology, theology, espetemology and government. There is no universal way to predict how humans behave on an individual basis because there are always deviants. A universal truth would be a pattern that everything obeys. An example is the law of gravity.
All objects have an attraction to all other objects.
This has been proven and is universally applicable. So universal truths can be universal on an objective basis or a universal basis. Just because humans act a certain way does not mean animals act a certain way. Universal truths mainly deal with science and math. In the long run, other civilizations don't care how we may have acted two centuries ago because it isn't applicable anymore.