Yep. But sometimes even arguing with the intelligent ones is both fruitless and frustrating. I was going back and forth with one such yesterday in a historical 'discussion' as to whether or not England and Europe would have eventually taken North and South America without any cooperation at all from the native populations.
I had my reasons why the answer was 'yes, eventually it would have happened anyway' and the leftist's reason why it would never have happened in a thousand years was based on the Irish potato. At that point I just walked away.
Yeah it is an accepted theory that the advent of the potato changed much . . . but it simply wasn't enough of a change to shut down the avalanche of other changes and technological, industrial, military, and mutual competition 'advancements' of those aggressive nations for a thousand years into the future.
The thing about even these educated leftists is that they never EVER contemplate anything other than what was rammed between their ears in college by academicians whom -- almost universally -- never stepped foot in the real world. They take theories as facts because it beats investing their time in . . . thinking outside the box. Sometimes I think that why and how they become leftists in the first place.