No.
"It's surely fair to say on this evidence that, if anything, being a Time Person of the Year™ makes individuals much, much more likely to be assassinated, not less*."
No, it is not. You've presented anecdotal evidence only. Please go back and document:
1. How many people have been named Time Person of the Year,
2. How many of those people have been assassinated, (calculate as a percentage of the total, please), and
3. The assassination rate of the general population.
That's a good start. However to be sure, you'll also have to compensate for confounding variables, such as the possibility that the selection of Person of the Year is biased towards people likely to be assassinated by dint of their position, power, wealth, etc.
Then, if the numbers pass rigorous statistical examination, I may consider it fair to say that.