Because most people don't seem to care about elders anymore and I know that when I stop having the energy to do things that I enjoy and I stop being desirable to people over somebody who's 20-30 years younger, I will be miserable.

Since I'm also an introvert who cares more about my hobbies and passions than dealing with people, the chances of me having children or being in a successful long term relationship are much lower than a regular person.

When people no longer want to deal with me when I lose my "appeal" than I know I will be lonely and I refuse to give society the last laugh.

Plus, I'm more than willing to sacrifice years off my lifespan to achieve some of my goals in life while I'm young.

So yeah, my comment wasn't meant to be any offense to somebody who is older or wishes to grow old, it was just my own opinion, which is probably influenced by my own emotional issues anyways.