A "memester" is a person who consistently uses memes to make a point rather than type out a explanation. This person is usually semi-literate.
The memester was unable to defend his point about patriotism in writing so he posted another picture of Trump wrapped in the American flag.
To "dumbfend" (v.) is to illogically defend an argument.
Example: When asked why he voted for Trump, Billy Bob dumbfended his actions.