Finding someone who is both willing and able to deliver explosives to a datacenter wouldn't be easy, the last stime something like that happen is 9/11. Throwing large masses on the other hand is not so hard as countries like Iran already have missile building capacity and are partners with actual space capable Russia.

Also, the super expensive data centers are great targets, probably much better targets than US can hit in Iran for example. What happens if those Nvidia chips that are churning the economy start to getting blown up by carefully de-orbited stones?

There were suspicious rednecks shooting out power stations a couple years ago.

The FBI routinely finds mentally ill people to convince/encourage/fund a terrorist attack and arrest them after they purchase materials with FBI money and call it a sting.

I don't think it's nearly as hard to find someone as you think.