The matter at hand is that evolutionists discard evidence that is uncomfortable.
A dino was most certainly found with tissue and bones in tact.
It's not clear to me what your problem is with scientists finding mineralized skin and soft tissue and even some proteins? This does not negate the Theory of Evolution. In fact, finding collagen Protein in the T-Rex gave scientists even MORE support for the ancestry that dinosaurs share with birds. Finding these proteins and soft tissues allows for scientists to strengthen their understanding of Evolution. Nothing in the ToE says that skin does not mineralize or mummify or whether we'll be able to extract proteins from million year old fossils. If you're looking for how or why that happens, your best bet is to study geology with a good dose of biology.