Uncle Sam is aware that large airbases cannot move and make easy targets for IRBMs, which they were.
They may not be able to move but as anyone who has actually been to the hot sandy place will tell you, airbases out there are generally bloody huge and the aircraft on them very well dispersed making the threat posed by an elderly IRBM chucked from a ner-do-well gulf state pretty minimal.
Of course the threat posed by a few C-802s against one big floating airfield in a relatively small piece of oggin may be slightly higher.