Imagine if you set away 20,000 BTC in a savings address, and then you fall into 10 years of coma. When you wake up, you find out that you don't own those coins anymore because some moron pushed a hardfork, and those that didnt uppgrade in time, lost every coin!!!
You do realize that it is most likely that you would have lost your coins in either case since this is about weakened encryption? There's just a difference between the community drawing out to a consensus in which coins get "destroyed" or a hacker exploiting the weakened encryption only to take away your coins. You'd have to choose the lesser of two evils.