"There is no bigotry like that of "free thought" run to seed"

In this quote, Horace Greeley is warning versus the dangers of severe free thinking. He recommends that when free idea is required to a severe level, it can cause bigotry. This suggests that when individuals become too focused on their own ideas and beliefs, they can end up being closed-minded and intolerant of others who might have various perspectives. Greeley is cautioning against the idea that being entirely totally free in one's thinking can in fact result in narrow-mindedness and bias. He thinks that true receptivity and acceptance of others comes from a balance of totally free thought and factor to consider for various viewpoints.