No, they're not required to clear security. It's been discussed here before (but it would be hard to find it via search since all the keywords are really common).

TSA critics have argued that TSA employees should be checked just like passengers every time they enter the checkpoint (to prevent them taking something Bad into the secure area) and every time they leave the checkpoint (to discourage theft).

TSA has defended their policy with various excuses:
- TSA employees are all completely trustworthy and would never ever take anything bad into the secure area. (Pay no attention to those employees caught taking bribes for getting drugs past the checkpoint, or the one who took a gun through for his friend, or the Alvin Crabtree.)
- Who would search the first TSA employees on the first shift in the morning?
- It's too time consuming for the poor TSA employees, who have to go in and out of the secure area all day.
- It would make the lines even longer and you don't want that, do you?
- It sends the wrong impression if they have to search their own people.

Okay, you get the idea. Basically, they can't be bothered and they don't care about the risks.
Yeah, that's been discussed before, too. (See, for example, this thread from 2010: Swabbing hands. Is this new? )The swab before the TDC idea was popular at some airports a few years ago - the idea was that you were waiting anyway so they'd get it out of the way - but hasn't received much comment lately. It appears that airports randomly pull these ideas out every so often to be "unpredictable".