Note that this list is list of places where if you are enterprise starlink customer SpaceX can provide you with physical ethernet port to plug your cable into when you want to handle your traffic yourself instead of that just going directly to the internet. That is kind of obscure service that even land-based PLMN operators offer but usually do not document in this way in publicly available documentation.
From the perspective of network design, the fact that this certainly is not exhaustive list of places where SpaceX has physical DC presence and physical reality it comes that some of these datacenters are selected based on the fact that the ground station is somewhere nearby (I would be surprised if there is even just one place on the list where nearby means "on the roof", because there is a lot of technical, logistical and administrative reasons why you do not want to put such a thing at a roof of a datacenter).
None of the original 5 buildings at Telehouse in London have any dishes on the roof but the new Telehouse South a few hundred yards to the South seems to have some on the roof but they don't look like they are for a SpaceX groundstation.
SpaceX groundstations look a bit different, they are a bunch of white domes about 1-2m in diameter, usually 8 or 9 of clustered together.
Here's an example in the UK: https://maps.app.goo.gl/Zy61dfdyp5xrq4w1A
It's handled by Arqiva here in the UK it seems, so no SpaceX branding on anything.
SpaceX also applied for two new grounds station sites in the UK, one a few miles West of Telehouse, south of Rainham. The other site is up in Harlow, Essex.
(I don't think any of this is secret, all of the info above can be found with some googling and scrolling in maps.)
> when you want to handle your traffic yourself instead of that just going directly to the internet
Isn't that skipping over the more sensible middle ground of a VPN, which is what is more common for at least small or medium sized business customers of mobile networks.