Don't confuse the folks with the facts!
Venus Temperature Still Uniformly High
This recent high temperature formation of Venus is consistent with its high surface temperature, > 462 °C (736 K / 864 °F) measured by Venera and Pioneer Venus (PV) probes, identical in completely different regions of the globe. The surface rocks are hot enough to melt lead and zinc. Proof that the temperature is driven by interior heat comes from the striking uniformity of this temperature - only one or two degrees deviation from pole to pole and on the day and night sides. Given the Venus day/night cycle of 117 earth days, it is obvious that incident sunlight, which is completely extinguished in the lower cloud layer, has absolutely nothing to do with the surface temperature. The global lower cloud layer, at 48 km over the entire planet, is also driven by the great interior heat...
http://www.firmament-chaos.com/planets_venus.html
Fair enough, but wouldnt an extremely thick atmosphere help to keep that heat in?