It's a matter of quantity of people the propaganda reaches.

In terms of quality, socialists repeatedly have success making an impact on this topic on other people. Right now there are people reading some of the comments in this post, particularly the longer comments, and they are genuinely being impacted by some of the things they learn or points made. Often silently.

The main issue is primarily the quantity of people that their propaganda reaches over the quantity of people that socialists can try to educate in a deeper and more meaningful way. I think it's worth looking outside the US though, across Europe most takes are significantly more measured, and across parts of the global south you get views completely untainted by the US propaganda because it doesn't reach them at all. Don't despair.