Why won't my Dad let me shop over the internet?

I live in Bangladesh and there's so many things like books, DVDs, Blu-Rays and video games that aren't readily available here. So, i checked amazon.com and found that they deliver to Bangladesh and asked my Dad to buy me a few things from the site (not expensive at all) with his international credit card but he keeps saying no. He says it has something to do with foreign currency transfer and divulging records to the government about spending dollars for international purchases as a consumer and not a business and how it can mess up the amount of income tax he has to pay. I don't get how buying $20 worth of DVDs would mess up the amount of income tax he has to pay?