I see people who fall for obviously flawed arguments as lacking intelligence and easily-influenced simpletons.
I am surprised to hear you have made such a conclusion. That's a little insulting to a lot of people.
Instead i believe people should think for themselves.
It wrong to believe people are stupid because you think they missed a flaw in an argument. Maybe they are thinking for themselves and you are missing their reason for supporting the argument.
Yup, they are just stupid.
There is no need for you to think of others as stupid. Many people believe many different things.