They seem to miss the most obvious - advertising is about promoting change. Conservatives are by definition more resistant to change, so advertising $$ flow towards liberals willing to be early adopters. We surely realize that younger folks tend to be more flexible and willing to try new things - i.e. by definition more liberal in at least certain regards. Now, we have somewhat competing, somewhat cooperating metrics - liberalism and access to cash to pay for liberalism. Youth will not buy a lot of Teslas, no matter how cool it might be or helping the environment, etc. So Tesla has to advertise a step back - slightly older with a ton of disposable income but still into social concerns - i.e. the wallet & speed probably isn't everything, there's still an element of social good in the buy decision.
This of course is the "early adopters", where a good chunk of advertising goes. But there are me-too adopters who want to be cool after it's safe. "All my friends are talking about Obama/Bernie, so I'm in too". Figuring out where these target consumers are lumpy is an art, one that Axelrod was particularly good at, and Facebook metrics both dig out and foment.
Then again, this social media thing might have a "liberal conservative" aspect to it - people who have stiff opinions but are quick to adopt new conservative trends, if that's not counterintuitive...