Warrantless DNA

If someone gets arrested, the police have the right to take his or her fingerprints. Also the Supreme Court has now ruled,  5-4,  that the police can swab the arrested person's cheek and register his or her DNA.  I'm not sure exactly what to think. I don't have much privacy. If you go on the Internet, what you write is open to being hacked and spread across the globe. That's the way it is, so I'm a little careful about what I send out. It's like when I go to Big John's to buy groceries. If I don't clamp one hand on my face, everyone in the store will know I eat Cheerios. I use one hand as a mask. I prefer to shop in private, and I can see fine by looking out between my fingers.