The only person mentioning "sex parties" is you. No one suggested that; it is a strawman.She didn't buy a plane for sex parties.
What she DID do was buy an airplane with a bedroom in the back, and she has used that plane several times with her boyfriend. And once there was an issue with her forgetting a bag with "embarrassing items" in it on the plane. So yes, if you buy a plane with a bedroom in the back and you use the plane with your boyfriend and take a bag of embarrassing items, it is a plane used (among other things) for sex. To pretend it's not would be either some pretty world-class naivete or a strong desire to defend a disgraced government official.
Had she wanted to buy an airplane for effective governmental transportation, she would have chosen one better equipped to transport government workers.