I see where you're coming from, but I'm going to have to respectfully disagree that the default view of these claims should be that they are propaganda.

If someone claims "both sides suck equally" or "the Democrats are just as bad," I agree with your assessment. It's disingenuous to frame the Democrats as being "as bad" as the Republicans when the latter are actively destroying our rights and championing a traitorous, fascist cheeto. The Republicans are undeniably worse, and anyone suggesting otherwise is either on their side or severely lacking in critical thinking skills.

That being said, I still don't think it's fair to treat "both sides suck" with the same level of distain as "both sides are equally bad." Indiscriminately dismissing opinions which point out the Democrats are also bad in their own (or similar) ways only serves to silence disapproval towards them. The Democratic Party isn't perfect, and they've made their share of mistakes in the past. While this election isn't the right time to rag on them, it's also not the right time to exonerate them and let them be above criticisms.

That kind of approach to grouping "both sides suck" with "both sides suck equally" and dismissing it as propaganda is also disproportionately silencing people with radically progressive views. A moderate liberal isn't going to have anything to complain about, but a "communist" (socialist) is more likely to take issues with the Democrats not taking a harder stance on pushing for things like universal basic income, more government oversight, higher taxes for the 1%, etc.