Nuclear propelled manned spacecraft will be much less expensive if
they can be assembled, operated, and maintained in LEO rather than HEO
when they are not traveling to some destination in the solar system.
However, in HEO, a nuclear propelled spacecraft can be left unattended
or even abandoned without danger to people or places on Earth. In
LEO, this is not an option. Any loss of control of the spacecraft
would result in the ejection of the reactors into a higher orbit and
the loss of many billions of dollars.

Modern automation can make loss of control of a spacecraft highly
unlikely. Backup manual control can make it even less likely.
Perhaps the risk could be made small enough that governments and the
public would be willing to accept it.