When talking about conspiracy theories, sometimes you can think about the number of people it would take to pull the conspiracy off, and how implausible it is that that many people can keep their mouth shut about it. Think about 9/11 - how many people would be involved in planting the hijackers, arranging them to get to the US, training them, etc (or, planting their identities and hiring actual suicide pilots, depending on the flavor of conspiracy you are following). It's hundreds of people. All it takes is one person feeling guilty to blow the whole operation. With that in mind, let's think about two recent conspiracy theories - one actively believed in, and one hypothetical.
The first is that the CIA/FBI framed Trump with the Russian Collusion narrative. As the story goes, this was a CIA operation to take down the president because...I don't know, they don't like him. How many people would be involved in an operation of this magnitude? We are talking about hacking the DNC, sending the info to wikileaks, hiring Steele, working with the Australian gov't to implicate Poppadopolous, Joseph Misfud and his handlers, framing Carter Page, etc. Every single facet of the operation would have a team with specialized skill-sets, and the operation would span multiple countries. It's a hell of a lot more than Comey, McCabe, Rosenstein, Mueller, etc., it includes computer hackers, forensics team, SIGINT & HUMINT apparatus, agents on the ground, staffers, stenographers, secretaries, analysts, etc. And, of all of these people, it requires 100% of them to be in on it - died in the wool Never Trumpers, unwilling to blow the whistle in the face of intense scrutiny.
Now, lets contrast that with my hypothetical conspiracy theory. In this one, Ukraine starts an investigation into Hunter and Joe Biden. They are immediately rewarded with all the military assistance they want, and Zelenskyy is a State guest of the White House. The conspiracy theory is that Trump asked Zelenskyy to dig up dirt on Biden. Back to reality though - an actual whistle blower blew the whistle. Someone wasn't on board with the operation, and that's why this conspiracy never came to fruition.
I think it's a common mistake to assume that organizations are completely in sync. Any particular group is likely to have different opinions and outlooks; it's a mistake to assume they all have the same beliefs and opinions. I see this at work - we assume everyone from another particular office has the same opinion on a particular topic, but when I talk to them individually, I realize there is infighting and debate there just as there is here. I think it's a mistake to assume everyone in the entire IC is anti-Trump. It's a mistake to assume they are all institutionalists, and work to serve their agency ahead of the country. That seems to be Tiabbi's underlying assumption.
I can't believe that the CIA is capable of pulling off an operation the size of framing Trump with the Russia stuff - not without someone blowing the whistle. It just takes one do-gooder to believe in his oath of office to put country over agency and the whole thing is up in smoke...just like Trump/Rudy's Ukraine operation.
I'm not here to say the CIA/FBI/NSA are 100% good and pure. However, I will note that we only know of their misdeeds from the actions of whistleblowers (some are in jail right now). We have actual evidence of conspiracy theories being confirmed because someone said something. The fact that no one from within the IC blew the whistle on Russiagate relegates the "IC framed Trump" meme to pure conspiracy theory.