No, TSA doesn’t look for weed, they look for explosives. Customs looks for weed. Never take weed on an international flight. That said it’s quite easy to travel domestically with it. Grinder just made a bad assumption.
They may not be carefully checking for weed, but you will get in trouble if they stumble across it.
A bunch of years ago a Portland Trailblazer got in trouble for having a somewhat large amount of weed wrapped in aluminum foil in his pocket as he walked through the metal detector.
I’ve heard that, while they are nominally looking for explosives, if they see anything of note, they will often make a call to other agencies and turn you over to them. An example includes their part in airport civil asset forfeiture. They are not allowed to take your money. But they can call their buddies, who can take your money. I assume they’re getting some sort of kickback, but that would be illegal.
It kind of depends on where you are also. For example let’s say you go to Colorado and buy marijuana products. If you get caught at the airport with those products they are legal there so no one cares. They may make you throw them away. However if you get them through security then you’re all good because no one on the other end is going to check you as you leave the airport. Edibles are very easy to transport.