I come across this one all the time, but it's usually in the form of "I know you're wrong, because person X made an argument that I don't understand, but this misunderstood summary of that argument says you're wrong".

Happens all the time with the old Donald Knuth chestnut about "premature optimization". Half the time I hear it, it's from people who don't want to optimize at all. http://www.joshbarczak.com/blog/?p=580