But "converting" my free time to gas, it gets worse MPG than cars.

In urban areas like the one I live in, most trips are faster by bike. Especially considering I always get the closest parking and almost never wait in a queue.

Where I live now, my bike ride to work is twice as fast as my bus commute, and in SF, it was about 30% faster. That said, my wife and I are both all season bike commuters, and because we make almost all of our trips (grocery shopping, taking our son to school, etc.) by bike, bikeability is a huge factor for us when we make housing decisions.

Nearly all the public transportation/cycling naysaying I read seems to be from people who didn't consider (or at least didn't prioritize) non-private automobile transportation into their housing decision, and typically, it's at great cost to them[1].

1. http://cityobservatory.org/transportation_housing_affordabil...

You might be interested by Ivan Illich's analysis in "Energy and Equity". The basic idea being that you need to factor in the cost of a mean of transportation into the speed of said mean.

The relevant part is cited in this article[1]. Of course, the calculation might be off for your specific case, so YMMV (so apt).

[1]:https://www.notechmagazine.com/2010/04/the-industrialization...

From https://www.oaklandca.gov/resources/bike-to-work-day

Besides being fun, biking to work is good for your health and for the environment. Take a look at all the benefits of riding a bike!

    Reduce air pollution: In the Bay Area, 43% of all car trips are two miles or shorter. For short trips, bicycling is an important tool to reduce air pollution: up to 70% of emissions from a 10-mile trip occur within the first mile.
    Stay healthy and fit: Bicycling to work is a great way to get exercise every day. The well-documented obesity epidemic contributes to heart disease, cancer, stroke and type 2 diabetes, which together make up 40% of the leading causes of death in Oakland.
    Save money: With gas prices unlikely to decline in the long-term, bicycling makes more financial sense than ever; a bike’s annual operating cost is estimated to be $120 (as opposed to. $5,000-12,000 for a car).
    Ease street congestion: Twelve bicycles can fit in the space needed to park a single car.

I get extra free time because my commute also counts as gym time.

If you haven't already seen this article:

https://peopleforbikes.org/blog/bicycles-are-instantaneous-t...

A gallon's worth of food is enormously more unfriendly to the environment than gas.

I wish I could find the blog post again, but someone did the math and found that for their commute, driving actually emitted less CO2 than biking if the extra calories came from meat. I think it still works out positive if the extra calories come from vegetarian sources, but the delta is much smaller than I'd hope. Of course, there are lots of other benefits to not using vehicles, but it was interesting to think about.

Does this include extracting the gas, refining it, transporting it and burning it?

Yes. You have to be careful which comparison you are making.

The one I am making is "If a human could eat gasoline, there would be orders of magnitude less environmental damage to do so compared to eating ordinary food"

Humans can't of course, but the guy claiming biking gets 3000 mpg equivalent is making the same comparison.

In truth if we're making atmospheric carbon loading comparisons between traveling by car of bicycle, the equivalent "miles per gallon" would be much closer to equal with cars and biking, especially if you fill yourself up with grain light, produce heavy organic diets.

Of course not. Those are externalized.

That chart is a little hard to read - what's the mpg equivalent of riding a salmon to work?