There are many forms of activism and it is important to keep in mind that everyone exists with different abilities in different contexts. Judging others because they aren't adopting the same strategy as you isn't going to build a winning coalition. Here's a quote from someone who was murdered by the SS and was reflecting on how stupidity is as much a sociological phenomenon:
It will really depends on whether those in power expect more from people's stupidity than from their inner independence and wisdom.
- Dietrich Bonhoeffer, After Ten Years
The idea that the DNC only has a messaging problem is to say we expect more from people's stupidity than from their inner independence or wisdom (ie Voters just need to be educated). A party that respects people would listen and respond to issues like Gaza or wealth inequality. The reason this strategy of educating voters doesn't work is because it isn't a problem with the intellect but of their oppression. Only by liberating fellow voters will they be able to act independently.
Judge not lest ye be judged.