Having a bunch of tanked up starships in orbits that are officially there for reasons that have nothing to do with their potential military use but can be used to destroy cities is also problematic. Especially when the operational security of them might be worse then standard military operations.
Delievering explosives to the target isn’t a trivial problem in war.
That said fully tanked up starships can also get into the explosive range of nuclear weapons. https://www.reddit.com/r/SpaceXLounge/comments/i4b5c0/what_would_be_full_stack_starships_equivalent_in/ suggests that the fuel that starship carries might be comparable to the bomb that hit hiroshima.
Having a bunch of tanked up starships in orbits that are officially there for reasons that have nothing to do with their potential military use but can be used to destroy cities is also problematic. Especially when the operational security of them might be worse then standard military operations.