Those dates are assumptions by the evolutionists, believing that is when dinosaurs existed.
However, the issue of diagenesis, or the chemical changes that occur to fossil bone after it is buried (dissolution, recrystallization, replacement of bone by other minerals) raises doubts as to the value of the isotopic signal to interpret the physiology of ancient animals and the environmental constraints they lived under. The inherent assumption of stable istope anaylsis of ancient bone is that apatitic fossils are isotopically unaltered. This notion has been challenged by several scientists whose conclusions undermine current interpretations of dinosaur physiology and paleoenvironmental reconstructions based on stable isotope analysis.
Nice try. Read the article more closely.
Here is the pertinent passage:
A best age estimate is given at 69.1 ± 0.3 Ma using the weighted mean from K-Ar and 40Ar/39Ar analyses from several tephra units that bracket the dinosaur-bearing horizons.They are not dating the bones, so the paragraph you quoted to show that chemical changes in the bones makes dating them inaccurate does not even apply.
They are dating tephra layers (volcanic ash) above and below the layers which contain the bones.
Conclusion: the bones are not contemporaneous with humans. They are off by about 69 million years.