Yeah it isn't... your meme is actually a stupider argument than you were given credit for.

He says the meme is basically 'x person can't do this, therefore all people affiliated with x can't do it either'
Where in reality your meme is
'X person can't do this, therefore all people affiliated with X can't do A,B,C,D,E or F'

Why not just say 'how can i trust someone who fell down the stairs that one time to tile my bathroom' -- its just as moronic.