I didn't read it as a personal attack. The OP's post is not that "unpopular" on this site because this website is full of libertarians. pg is one, I believe. Most entrepreneurs of course, support capitalism and free markets. In fact the proposition that "a nonprofit/charity will never make as big a difference as a true for-profit vehicle that is pointed at the same problem" likely resonates with a majority of users, although I can't really provide a figure, this is from my general experience with the site.

I don't think that the parent post is supposed to be an attack on the opinion, but pointing out that it's actually popular.