They haven't found dinosaur DNA, it doesn't last long enough, so there is nothing to sequence. All they have found is some protein, not cells with genetic material.
'Organic' doesn't even mean 'genetic material' anyway, it means 'carbon based' & usually refers to amino acids or proteins, both of which can last millions of years under the right conditions, it's very rare, but it can happen.
So although the DNA will have broken down not long after the dinosaur's death, it is possible to extrapolate what part of the organisms genome may have looked like by looking at the structure of the protein that the organism was constructing & from which the organism was constructed.