No sane person of any political persuasion thinks humans are "solely" the reason for climate change. I would even include both Jill Stein and Donald Trump in the category of "sane" in this context (but not most others). This is the most strawman comment I think I've ever seen on the internet.
Without humans sending great gobs of CO2 into the atmosphere the climate at this point would be starting to tip into another ice age. So, yes, all scientifically aware humans agree that the current cause of climate change is human induced. It can be argued though that warming is better than freezing. Personally, I expect say 100 years from now when warming is on the wane we'll start burning fossil fuels just to avoid an ice age. But in the mean time CO2 is a bad thing. The golden mean is what we are seeking.