Either he is, or then was, playing for both sides and would only expose what he was allowed to expose, and with that one he found that he wasn't allowed a bit too late, or he never actually had the info and was only trying to get attention, and hadn't thought through how to explain not actually giving out anything in the end, or the original plan for that failed in some way.

If he isn't compromised, as some people here seem to suspect, embarrassing him publicly would probably have been something the black hats would have liked, so presumably it's possible enough that the whole thing was some sort of bait and switch from their side, Tucker thought he had the information but never actually did, or he got a glimpse but it was then stolen one way or another before he could secure it, and he was left having given a promise to his audience he could not keep.

Or he got threatened, believed the threat and decided he didn't want to take the risk of ending as a suicide who got shot in the back or fell out of a window, or just had a convenient accident or became a victim of street crime or a home invasion. That game seems to be pretty hardball, considering how often people who might have been able to expose something have had those accidents or "committed suicides". And maybe he feels safer now so now he is willing to take bigger risks.