Does the TSA just make this stuff up?

​I was in San Francisco for the Game Developers Conference last week and had yet another head-scratching encounter with the TSA on my way back.

​I was rushing to catch an early morning flight out of San Francisco Airport and I had a single carry-on bag that included a few souvenirs I picked up for my wife.  One of those items was a small jar of hazelnut spread (like peanut butter, but a different kind of nut).  I won't go into the normal ridiculous details of how much time I spent in security checkpoint lines (which I had to go through twice, as a punishment for riding the subway into the airport, I suppose).  However, the second time I went through a security checkpoint, my bag was pulled and the jar of hazelnut butter was brought into question.

​Here is the approximate conversation:

TSA Agent:  You can't take this through security; it's more than three ounces.​

Me:   Yeah... but it's not a liquid, plus the other security checkpoint let it through with no problem.

​TSA Agent:   Well, you can't have more than 3 ounces of liquids, lotions, or gels. 

Me:  This is like peanut butter.  It's not a liquid, a lotion, or a gel. It's ground-up nuts as you can clearly see.

TSA Agent:  Basically, the rule applies to anything that is not hard​.

​I was then given the option to go back and process the jar of hazelnut spread as a check-in luggage, or throw it away.  Since I couldn't waste any more time, I chose the latter.  

However, I'm left with 2 questions regarding the nebulous policies of the TSA:​

1) Is there really a rule so vague and ridiculous as "You can't bring onto a plane more than 3 ounces of 'anything that is not hard'"?​  Or do their agents have the latitude to make this stuff up as they see fit?

2) If there is such a rule, should I be worried that one TSA scanning station in the same airport, 10 minutes earlier did not catch and enforce my infraction, when a second, essentially identical station did?  ​

And of course, we still have the basic question as to whether it's worth ​approximately $8 billion dollars of our taxpayer money per year to pay these people to (sometimes) ensure that peanut butter and similar substances don't make it onto planes, while routinely letting loaded guns get through and perpetrating all kinds of abusive behavior.