I'm not sure what that means (or if it's really true). The temperature at night doesn't drop to almost (absolute) zero; the oceans don't freeze; so plenty of the Sun's energy must still be present.
The initial statement was power/area, the instantaneous energy input from the sun, given as 1GW/sq km. The energy input from the sun at night really is pretty much zero.
The initial statement argued that because organisms are "fine" with 1GW/sq km, they therefore should be fine with the additional heat of a datacenter. I disagreed with the conclusion, not the number.
The second statement was that "OTOH, that 1GW drops to almost zero at night." It may be a literally true statement on its own, but it's misleading in response to a statement that absolute zero isn't a realistic basis for this discussion.
