All Trump voters are racist, therefore all Biden voters are Communist.
See how that works. You are the same as them.
Bad comparison.
Trump is a racist/bigot. This is obvious, both from his rhetoric (neo-nazis are fine people), and from his actions (muslim ban). Anyone who votes for Trump is likely aware of that, has evaluated his words and actions, and said "Yup, I'm fine with that". Even if they don't think they are racist, or recognize Trump as a bigot, they are still giving their seal of approval to him.
On the other hand, Biden is not a communist. Communism as an economic theory involves direct state control/ownership of businesses. Being in favor of social programs and/or greater economic regulation (things that Biden does favor) does not make someone a 'communist' since it does not involve the type of direct ownership/control... at best it would make them a 'social democrat'. So someone could vote for Biden without being a communist (or even being 'pro-communist') because the label does not apply to Biden.