Why are elderly so sarcastic and brutally honest?

Today my laptop got stolen. No joke! I am very furious. I was going to use the restroom and I asked this elderly couple to watch it and they would. After it was gone. I was like, "Did you see someone take my laptop." And they said they did and tried to stop. I yelled, "Why did you let them?! I ask you to do one favor!" The man said, "Don't to raise your voice at us. We're not going after her. Besides you're responsible for your own shit young lady." His wife said, "What did you expect us to do, go chase after her and clobber her? It's YOUR fault for being so careless about your laptop."
I payed $400 for it! I need to get it back. I need to make signs.

No rude, sarcastic, blunt, sassy comments please. I'm very upset.