Heck, I don't have PTSD but I don't particularly like seeing sexual violence in movies or television shows and more than once I wish I had been warned about it ahead of time.
From my point of view, trigger warnings are courteous. Its not my job to tell people how to live their lives. If someone asks me in good faith to let them know before I talk about something that might disturb them, I take that seriously because I'm not a jerk.
The idea that trigger warnings constitute some kind of creeping Orwellian thing is nuts to me. The whole point of them is "I'm going to say this!"
try not to be one.