Stupid advertisement

I was stunned by an advertisement on national news paper (Kantipur) of Nepal dated 8 sept. 2010. The ad was about a business sale of TATA car (see picture). The message is in Nepal language and in its translation, the message is: Do you know? This Dashain, only dumbs don't buy TATA.

How can a company call all the people 'Dumb' if they don't buy a TATA car?. If I won't want or I don't have money to buy this car, am I dumb? Do I need to buy this car to be smart?. The company is trying to sell their products through nice advertisement but they don't have right to call others 'dumb' just for not buying their products. I also don't understand how such advertisement could be published in national newspaper. If someone sue both companies, how can they prove that 'TATA not buyers are dumb". The advertiser and publisher might have not realized that this ad could be most stupid in the market.