You're entirely right. Any sort of computation in space needs to be fluid-cooled or very sedate. Like, inside the ISS, think of the laptops as actively cooled by the central air system, with the local fan and heatsink merely connecting the laptop to air. Also, they're shielded by the "skin" of the station, which you'd think is a given, but many spacebros think about unshielded electronics hanging out in the aether like it's a nude beach or something.
I'd imagine that a serious datacenter in space would need to concentrate heat into some sort of battery rather than trying to radiate it off into space. Keep it in one spot, compress it with heat pumps, and extract another round of work from the heat differential. Maybe do it all again until the differential is small enough to safely radiate.