Hence the inherent immorality of essentially lobotomizing a sentient being against its will. That was the central conceit of Threepio's (neutered) sacrifice - that having his memory wiped would erase his humanity. 
Q: Would Threepio's sacrifice mean anything if wasn't sentient?
		
		
	 
 Is C3-PO actually sentient though? 
 On Endor it was against his programming to impersonate a deity. Ergo how much free will does he actually have?
 Here's the problem treating Star Wars droids as organics. Parody but you'll see the point. Assume Palapatine went in a different direction. 
 Galactic News Network. It has been a year since Chancellor Palpatine introduced the droids voting rights act granting citizenship rights to droids. We are here to interview V1-TE on their opinion of the Trade federation-Techno Union merger. 
V1-TE "Vote Palapatine". 
 Reporter "That's great V1. VK-47 what's your opinion"?
VK-47 "Palpatine is my favorite meatbag".
 "And B1-V2 what's your opinion"?
B1-V2 "We love Palpatine Roger Roger". 
 GNN: "Breaking news the Senate has just announced a 5% tax raise. The money has  earmarked for 1 trillion new V0-TE droids. GNN welcomes our new citizens.
 Even in old Legends which dif explore droid sentience there's a species of sentient Droids (not manufactured by Republic/Empire,) experimental models (IG series, Guri) and R2 (debateable) that actually have free well. Those models are similar to Data from Trek  cutting ng edge prototypes. 
C3-PO argueably is an intelligent walking Google translate machine.