Can't refuel ships at my empire own planets, ships only refuel at Gas Stations, Resupply ships and Starports. But they gladly refuel at AIs empires planets and it's even possible to order refueling at others empire planets via context menu.
For example, here mine colony of LZ145. It has all both kinds of fuel.
The gas station on a picture bellow hasn't been build yet, so ordering ship to refuel at nearest refueling point, orders it to fly to nearby Gas Stations, Resupply ships or Starports at others stars.
But as soon as other empire has colonized moon at the same system, it's become possible to refuel ships at them and "refuel at nearest refueling point" option now orders ship to refuel at their colony too.
Also there is no context menu while right clicking on your empire own planets with a ship selected, cursor just changes to load / unload troops or patrol actions.
If AIs empires could refuel ships at their own planets, it could explain why they colonize so fast