The purpose of a greenhouse is to grow plants indoors when its too cold for them to grow outside. Like you pointed out, CO2 helps make the greenhouses warmer.
Also --neither of the links you provided disputes the fact that CO2 has properties that act as insulation. Because its a scientific fact all scientists agree with.
You also ignored the fact that I mentioned that man made CO2 emissions may only contribute to a small percentage of global warming. The "scientists" in the links provided claim that our global temperature increases are normal, but they conveniently overlook the fact that its now warm to melt ice that's been frozen FOR THOUSANDS OF YEARS.
Which is not normal -- right ?
By the way, you may want to find out who paid for the research for the scientists who refute the CO2 explanation. A lot of times their salaries are paid for by oil companies. Something to think about.