This to me is a traditional view which remains persistent until the very day.
My mother considered gambling as playing with money. She sternly reminded us not to gamble. When I was in college, there was a hot debate within the church whether or not to accept donations coming from dirty sources such as gambling. And in Islam, gambling (maysir) is haram (forbidden). [1]
I have a friend whose father would not serve the family food bought using gambling money.
And just a few years ago, our Education Secretary shunned billions of state-funds because they are coming from gambling. She didn't think it moral and proper to buy books and even build classrooms using the dirty gambling money. [2]
What are your thoughts on these? Do you agree with it, or you consider these as old-fashioned views?
So many factors and it depends on your status, and the society where you belong, like if you live in a country where shariah is the governing rules and Islam is the religion, you should respect what your religion preach to their followers, but if you are living in a liberal country and where gambling is very prevalent, then I don't think you will consider gambling is dirty money.