When I’ve visited the big data centers, they had gates and security relatively far out from the buildings. How would you get close enough? It’s not like the World Trade Center in 1993 where you can just drive up next to the building. (It’s also not like the World Trade Center in 2026 where there is an anti-terrorism perimeter of steel-reinforced concrete bollards, but somewhere in the middle.)
Of course there are also data centers in the middle of cities but these are smaller.
Rather than going into detail, getting myself on yet another watchlist, and possibly inspiring someone to do something both criminal and counter-productive, I'll just quote Patton:
Fixed fortifications are a monument to the stupidity of man.
Of course there are also data centers in the middle of cities but these are smaller.