In the main directory's data folder is a folder named 'policy'.
In the folder are the 7 main (playable) races.
If you open each 'xml' file with notepad++, for example, scroll to the bottom to reveal these lines.
<IntelligenceMissionCounterIntelRatio>0.34</IntelligenceMissionCounterIntelRatio>
<IntelligenceMissionAggressiveness>1</IntelligenceMissionAggressiveness>
<IntelligenceMissionCaution>1</IntelligenceMissionCaution>
<IntelligenceMissionAllowSabotageConstruction>true</IntelligenceMissionAllowSabotageConstruction>
<IntelligenceMissionAllowStealTerritoryMap>true</IntelligenceMissionAllowStealTerritoryMap>
<IntelligenceMissionAllowStealGalaxyMap>true</IntelligenceMissionAllowStealGalaxyMap>
<IntelligenceMissionAllowStealOperationsMap>true</IntelligenceMissionAllowStealOperationsMap>
<IntelligenceMissionAllowStealTechData>true</IntelligenceMissionAllowStealTechData>
<IntelligenceMissionAllowSabotageColony>true</IntelligenceMissionAllowSabotageColony>
<IntelligenceMissionAllowDeepCover>true</IntelligenceMissionAllowDeepCover>
<IntelligenceMissionAllowDestroyBase>true</IntelligenceMissionAllowDestroyBase>
<IntelligenceMissionAllowAssassinate>true</IntelligenceMissionAllowAssassinate>
<IntelligenceMissionAllowInciteRevolution>true</IntelligenceMissionAllowInciteRevolution>
They are identical for each race & thus...very easy to modify for each race (if you want them to all be identical) by editing & pasting & copying.
Simply change 'true' to 'false' for any category you do not wish the race/races to be able to perform, such as stealing tech, or assassination, etc & problems solved. (?)
I have not tested this, but this does appear to be a quick solution for those that deem espionage too good or too bad.