Well ..
One, there's a tweet up thread indicating the Mets were interested in JBJ
Two .. The Mets don't have any players that would interest the Sox other than their starters. This should also be appearent to the Mets
So one can logically assume Bradley would be part of a deal for a Mets starter if they are sniffing around.
Obviously JBJ would not be enough. But does he have more value than the departed Margot? Who was usually considered robe the centre piece in any SP swap. You'd have to think so.
So could JBJ/Owens/Devers plus lottery ticket fetch a Harvey?
One, tweets don't mean a whole lot. Quite especially from a general account that no one has to assign their name to. Not that that makes a difference anymore, because, well, the media just throws shit against the wall these days and if they are right, they scored. If they're wrong, "hey man, it was just a tweet about a rumor I heard from a source I cannot divulge. It's not like I wrote an article about it."
Second, Bob's point is that if they are going to move one of their assets, why would they do it for a redundant piece? Any one of their SPs would fetch a nice return. As you mention, while the Red Sox's interests appear apparent (SPs), the Mets' seem pretty apparent as well with any logical assessment of their roster (see E5Yaz's post). So it makes no sense that they would be using a young, cost controlled SP in trade to acquire a CF whose main attribute is his glove, with a pretty large question with his bat, when they already have one of those and need offense, given they are going to see Cespedes is definitely gone and Murphy might also be.
In summary, his post could also be read as "that tweet is at best nonsensical and at worst complete bullshit because anyone who pays attention and knows what they are talking about would realize that's a terrible match for the specified piece coming from Boston and it was probably an intern that posted the tweet".
And no, that trade offer would not garner Harvey. JBJ is redundant, they have Wheeler coming back to fill a slot opened by trade/they could easily sign a cheap FA to fill the back end and David Wright is their 3B until 2020, so Devers is immediately discounted in blue if you want to play him elsewhere.