Yes, cars do produce more CO2 than air conditioning, but in the context of CO2 emissions, you can't just compare "equivalent of gas gallons".
First, not all electricity is generated from fossil fuels (63% in the US, much less e.g. in many parts of Europe).
Second, to produce 6000 kWh of electricity from fossil fuels, you have to burn much more than the theoritical amount, because the efficiency of conversion is much lower than 100% (although in cold climates you may use combined heat & electricity production).
In the end these are irrelevant details, as we must stop burning fossil fuels anyway. Every part of the chain is important, and the argument "but x produces even more CO2 than y, so I keep using y" is of course stupid.
That is not true globally. I live in Kuwait, which can get up to 140F during the day in the summer.
At any rate if you want numbers (since people are crying about research without doing any of their own) here are some: https://news.ycombinator.com/item?id=19438999
Another way to look at (and there is a lot of data on this) is which nations produce the most CO2 per capita and then work backwards asking why that is.
Also, most the countries here have a higher than average population density compared to the global average due to a small geographic footprint.
An air conditioner typically consumes in the neighborhood of 4kW, less than half the day, less than half the year.
So, being generous, 6000kWh annually for air conditioning.
Gasoline has the equivalent of 34kWh/gallon, which implies air conditioning uses the equivalent of 176 gallons of gas per year.
The average person in the US drives over 13,000 miles per year. The average car gets 25 mpg. That is 520 gallons.