if I patent a microwave and specify exactly how it works, that part can't be trade secret
BUT if my trade secret is on using ruby diamond for deluxe premium microwave lazor THAT isn't specified on the patent, well that be a trade secret
but trade secret CAN ONLY BE PUNISHED IF someone insider leaks the info -- not much can be done if some junk collector finds out about the ruby stuff
But lawyers are prone to using scary phrasing, even if that phrasing has no bite, and are free to write strongly-worded letters.
"I see that you've been publishing the privately-held, trade secret tomato processing technique I developed -- on the Internet! Now, tomato processors everywhere can see it! I'm really pissed! I demand that you stop doing this immediately! In fact, if you want a full enumeration of whar I really think about the terrible things you're doing, then I further demand that you pay me $25,000 for that effort!"
...it's got no bite, but it's a letter. It can be drafted and sent.
(It can also be ignored upon receipt.)