I think that's true, but because of bad prosecution and not because of party affiliation.
The articles of impeachment,
https://cicilline.house.gov/sites/cicilline.house.gov/files/documents/ARTICLES - Final 1030 - 011121.pdf, have
I'm no lawyer, but it sounds like the charge is saying Trump said some things on January 6 that caused the riots. That means all the other things he did before January 6 (other than publicizing the rally) and his attitude after the riots started are irrelevant for the charges.
Both the articles of impeachment and the evidence the House Managers presented at the trial left out that Trump told the people at the rally to be peaceful (
https://www.npr.org/2021/02/10/966396848/read-trumps-jan-6-speech-a-key-part-of-impeachment-trial)
The jurors, or at least the ones who had any chance of voting to acquit, probably knew of this before the trial.
So I think the case as presented was weak mostly because of the narrowness of the charges. The Democrats could probably have produced better charges, but they wrote them without thinking too much. At least they can say the won a majority vote, just like in 2016.