... spent a lot of time going through them making sure that all of his activities were redacted or just removed altogether, so he could expose all the DEMs who he was sure would be in them ... Unfortunately, he didn't find them there, or not enough of them there to make it worth while ...
Not just his activities but probably many of his donors.
... and he didn't want to risk that they might have missed some of his information so it would be best to just abandon the whole idea as a safety precaution! He still might change his mind and release bits and pieces in hopes of damaging specific DEMs, if they irritate him enough!