I was. HFT is an interesting and rich problem on its own, but its complexity and difficulty pale in comparison to cancer research.

And I don't get this "our brightest minds wasted on HFT/adclicks/etc" argument. Research positions at universities and labs are extremely competitive. There are hordes of brilliant people beating down the door to work on the problems that matter. The bottleneck is funding. A smart person who chooses to work in a higher-paying field and contributes enough financially may well have a larger impact on overall scientific progress than doing research in person.