The quick response to all of this is that we aren't tunnel visioning on climate change. We're trying to address fossil fuel use, transportation, food, etc. all at once.
It's not like you can realistically have everyone working on the same aspect of the problem at once. That's just horrifyingly inefficient.
- - - Updated - - -
You can try and make it as ridiculous sounding as you want, but methane is strong greenhouse gas acting on short timescales, and livestock produces a lot of it. That's just the reality, and that's not changed by writing 'cow farts' or by straw-manning it to be the 'source of global warming' when nobody has ever said it was more than just a part of global emissions.