The strategy is in the article itself: some things were altered but the core of the documents were accurate and the investigation was sound since Russia hacked the DNC and worked with Trump to influence the election. Nothing of substance has really changed on the left.
The Dems really need the Russians hacked the DNC server narrative to hold even though it is solely based on the word of Crowdstrike.
The more plausible explanation is Seth Rich downloaded the email and gave them to Julian Assange. Without the Russian hack, the whole election interference narrative implodes and the DEMs/DS go down forever.