I'm pretty sure, as a millennial, I'm supposed to agree wholeheartedly with this sentiment. But this "individuals should be able to do whatever they want" mentality is harmful to society as a whole. Society is made up of individuals. The actions of individuals do in fact affect the rest of society, even when it's not immediately apparent how they do. We don't live in a vacuum.
People making intentional, reasoned end of life decisions is beneficial to society. Viewing death as something to put off as long as technologically possible is not a universally good thing.
I don't see why the way one chooses to die should affect society as a whole, specially when it's done on the terms described. The fact that they were courageous enough to live the entirety of their lives the way they wanted to is to be admired and respected, even if you don't necessarily wish to follow such footsteps.