Translation:The young man cannot be stupid because he studies mathematics.
Yes, but wouldn't that mean the fallacy plagues the people, in other words the belief that someone cannot be stupid for studying mathematics, rather than it meaning the people themselves being plagued with stupidity in spite of studying mathematics?
But I guess that may have been exactly what they meant to say, in which case fine, and also, yes, rather eloquent :)
Plenty of smart people are not so good in maths. Lots of times, they are simply not taught well. Look up 'math tricks' on Youtube to see math tricks they probably didn't teach you in school. https://www.youtube.com/results?search_query=math+tricks
He can't be stupid because he studies maths, but he could be stupid for some other reason.