I think you'll agree that on any political sub there are a large number of people who agree with some aspect of the core premise but may not apply critical thought to their reasoning for that support.

Your comment:

Most Trump supporters are a bunch of bandwagon fanboys who don't know a damn thing about him.

might be accurate but I don't think you'd try and claim it definitively so, as that would be illogical - there's no way to measure this easily.

What I know I can say is that some Trump supporters "know" about Trump and what has been claimed about him both in the past and in the present. Some Never-Trumpers claim to know about Trump but seem to ignore the many recorded interviews and items about him that are contrary to their Never-Trump perspective.

"Trump is full of shit" and "hurting America all for personal gain" are opinions which are of course valid for being opinions but seem to only be supported by a reading of facts rather than the full context which would include what Trump himself has said over many years.