SpaceX plans to launch 120 kW satellites, each weighing 1.7 tons. Let's be conservative and say it ends up being a 100 kW satellite massing 2 tons. Let's be conservative and say Starship can launch 50 tons to orbit for $20 million ($5 million more than a Falcon 9 launch).
50 kW per ton x $400K per ton = $8,000 per kW = $8 million per megawatt in launch costs.
That means a 100 megawatt orbital data center will cost $800 million to launch.
You need about 833 satellites for 100 megawatts, so let's round up to 1,000 satellites. Let's say one of these satellites cost $3 million (that's probably high, but let's go with that for now). That's about $3 billion for satellite manufacturing.
Bottom line: It will cost SpaceX $4 billion to launch a 100 megawatt data center.
Anthropic is paying SpaceX roughly $50 million per megawatt per year. SpaceX could sell access to its data center for $5 billion per year. Assuming the satellites last for 4 years, that's $20 billion in revenue from $4 billion in costs.
Please correct my math/assumptions, but this rough calculation shows that SpaceX could be right and Morningstar could be wrong.