Of course we humans contribute to it. It's our hall mark. In the general scheme of things, we burn things. It's what we do! That there are several billion of us doing it has an effect on the things.
The question is, can we or should we, do anything about it. Banning SUVs is just as silly as claiming humans are not responsible for the increase.
If science actually and reliably predicts that sea level is going to rise, then we should start constructing dykes. Attempting to reduce the habit of burning things enjoyed by several billion people is ridiculous!
"Silly" is a an exaggeration in light of all the natural sources of CO2 increase, the fact that we are currently near the peak of a temperature cycle, and the argon data described in this study. It's relevence drops further when looking at the unconvincing temperature data.
However I agree that atmospheric CO2 data from multiple ice core samples consistently showing the highest level in 400,000 years is suspiciously correlated with the explosion of industrial growth. It may be that human activity has added significantly to naturally elevated CO2 levels.