All projects involve some sort of sacrifice, you might as well argue some people don't want to do all that hard work yet still compete in the top ranks.
I see no problem with competitions that are limited or regulated in some way, like the Special Olympics. Indeed, that's largely the theory behind any competition- you can't just wear a jetpack to a vaulting competition or pull a knife on a fellow hockey player, because the point is not simply "Do anything and everything to achieve Goal X." If nothing else, that sort of reasoning tends to defeat the point- imagine if most sports consisted of teams trying to prevent their rivals from ever making it onto the field.
Look, there are many dangerous sports that we don't object to even when they shorten their participant's lifespans.
That tends to be because it's an unavoidable aspect of the sport, not because we just don't care. Boxing consists of two people punching each other until one can't fight anymore; there's only so pleasant that can get. Racing consists of going really fast, which means that sometimes things go really wrong. We don't let boxers use brass knuckles or allow racecar drivers to use wheel blades on the notion of "Well if you can't handle it stay out of the big leagues," because it's not really necessary or productive.
And regarding everyone using the drugs and evening the playing field shortening everyone's lives and generally not changing anything, I argue that it's already a part of Olympics already, extensive training isn't exactly ideal for a person in their lives, socializing and being with family is arguably far more valuable.
This also tends to be an unavoidable consequence of the sport. There's no practical way to limit how much training someone's allowed to do, because training is a natural part of most activities and frankly the athlete's time is their own. Saying "Well arguably socializing is more important than practicing your vault" is a non-argument. Trying to argue that because there's some negative effects we may as well allow any and all negative effects isn't reasonable; you'd be arguing, among other things, that outright assassination between athletes should be permissible.
What we should focus on, is probably living standards, I think it's justified for a person to increase the quality of his/her life by doing what they want to do, even at the cost of shortening their life spans.
I'm not sure where you're going with this. Performance-enhancing drugs are not symptomless except for decreasing life expectancy.
I think there is merit in the claim that people should have to break themselves to compete with each other, but this point is not consistent with the current levels of how much people allow others to train or practice even when they'd be doing other things instead to compete at the top level.
I'm not certain I follow, but the last part sounds like you're saying "Instead of training all the time, let them take steroids to achieve the same effect, then spend the rest of their time enjoying life instead!" This doesn't make any sense, since people trying to get to the absolute top will spend all of their time training
in addition to any chemical enhancements, not instead of them, and if they didn't, it would either mean they didn't want it badly enough, meaning according to you they shouldn't be competing in the first place, or the drugs are completely capping out their potential, in which case it'd literally be a competition between drugs, as Darvi suggested.