Of course you can. Gullibility is a blameworthy trait.
If you want to blame someone for that then it's up to you.
The problem with your approach is that it involves both a double standard and a distancing of yourself from "the deplorables."
I'm pretty certain that somewhere upstream I said something along the lines of 'we are all susceptible to...'. I'm certainly not excluding me from any of the faults that have been discussed. Please don't consider this to be an 'us v them' position.
We could fold over your own approach against you: "You can blame them if they are a dishonest person," where "dishonest person" just means "someone who does not agree with me." Given that you cannot flesh out your notion of "honesty" beyond a question-begging redundancy...
Dishonesty is a pretty easy term to define. So much so that I shan't even bother linking to a dictionary definition. But let's use an example. Say someone is arguing for less immigration. There are reasonable arguments to be made for that position. But let's say that someone blames a lot of crime on immigrants, therefore there should be less. You'd be quite entitled to post links and facts and figures to show that the crime rate among immigrants is lower than the general population, so they can't use that as a reason. And you'll generally not get a response to that because a) it's true, and b) accepting it removes one of the main arguments that the person wants to use.
So that's now off the table. You can move on to taxes, job rates etc. But what you will often find is the same argument used by the same person further downstream, or in a different thread. They might say that they actually believe what they are saying. But they have no evidence for it and have been presented with evidence to the contrary. They are then being....what was the term..? Ah yes. Dishonest.
Your account is also wrong. There are no contextless culpabilities. There is no material proposition that cannot be honestly held. Folks who think such a thing usually can't see beyond their own bias. For example, there are honest flat-earthers. There is no proposition such that to hold it and to hold it dishonestly are the same thing.
I'm pretty certain that flat earthers are honest, law abiding people. But you can actually prove to them that some of their arguments are wrong. So they'll ignore that argument and head off somewhere else. That's being dishonest.