The Short Version
No credible source documents James Vasanthan making a statement that Tamil society is not as intelligent as commonly believed. His documented public controversies involve remarks about composer Ilaiyaraja and criticisms of Tamil film industry practices — not a broad judgment on Tamil society's intellect. His own quoted clarification explicitly disclaims any intent to insult the Tamil community as a whole, and the apology was tied to the Ilaiyaraja dispute, not to any claim about societal intelligence.