This is an example of idiomatic writing that is common in some dialects. The example sentence posted is actually not grammatically correct. The writer uses the wrong preposition, and nobody caught it for correction.
Tourism professionals have an obligation to provide tourists with objective and honest information about [or regarding] their places of destination...
This would be a more correct way to write the same idea.
Now, the preposition "about" introduces the prepositional phrase "about their places of destination". The entire prepositional phrase provides the reader a better understanding of the "objective and honest information" in question. In this case, it tells us that the information has to do with the "places of destination" of the customers of the tourism professionals.
"Places of destination" is also an unusual (and redundant) expression. It means the same thing as simply saying "destinations". The following sentence means exactly the same thing as the example sentence:
Tourism professionals have an obligation to provide tourists with objective and honest information about their destinations...