Are you suggesting that the only way you could have stold (sic) a sticker is by peeling it off? That's not the only way.
You can be as mad as you want but he is not under any obligation to sit there and wait for you to find your registration. You're required to provide proof of current registration upon request. Not 5 minutes later and not 10 minutes later. I'm not sure what do you want us to tell you or how else to help you resolve the issue.
There is a good reason why the registration card has the serial number of the sticker. Now...
To get a replacement sticker, you can go to the DMV.
To get the citation dismissed you can pay $25 or you can take it to court and move for a dismissal. And understand that the $25 is simply because you were unable to provide a copy of your registration upon request!
Those are your choices!

