The reason why there even is a "CO2 equivalent" is because methane itself traps heat in the atmosphere much more strongly than CO2.

But the half life of methane in the atmosphere is believed to be just 10.5 years; CO2 is stable. So calculations of CO2 equivalent have to define a time period, and usually the time period defined is relatively short (eg 100 years, or even as short as 25 years) to get a scary CO2 equivalent.

Over a longer time frame, organic methane sources simply aren't important.