It's really very simple, all berating-related CO2 is CARBON NEUTRAL. **CARBON NEUTRAL**. ZERO NET GAIN IN ATMOSPHERIC CARBON DIOXIDE LEVELS.
Every single atom of CO2 exhaled CAME FROM THE ATMOSPHERE. Plants take CO2 and turn it into sugars, animals eat those and turn them back into CO2.
The reason fossil fuels are bad is that you're taking CO2 that has been accumulating for millions and millions of years and releasing it all in one go, thus it's a **POSITIVE NET GAIN** ATMOSPHERIC CARBON DIOXIDE LEVELS.
Anyone trying to equate someone's breath with fossil fuels is a LYING HACK FOR THE OIL INDUSTRY.
The only possible link to any greenhouse gas emissions is if you eat slightly more, but again that's only because our food industry uses so much fossil fuel.