Well, it's not immoral to make profit, it's actually funny, but take the opportunity to tell them this:
Far beyond the invention of a technology, a decentralized cryptocurrency is potentially the beginning of a broad social disruption. Just to name a few ones: of the current monetary and financial system, of government self-financing capacity, perpetual indebtedness and growth; of the heavy govermnet interference in the economy, and also of the today's false relevance of the political class and its inconsequential electoral promises; - in short, of any structure that reinforces control and concentration of wealth and power to the detriment of individuals. And, in a positive way, it marks the beginning of an industry in which the mere participation incites a new way of understanding money and society's economic structure.
In creating Bitcoin, Nakamoto, in addition to freeing people of the burden of a financial elite that believes to be the world's economy owner, decentralized the key factor "trust" and returned it to ordinary people who now only need to remember that behind everything there is an unbreakable protocol. He offered people the possibility of trading in a fair monetary system, something that they do not enjoy today neither they notice it's missing.
It's nice to make a profit, but it would be nice if you help to spread the word too.
=)