Allowing drugs is a stupid idea. It's not a level playing field at all. Clean runners would be penalised. Why would you see that as desirable?
I wouldn't see it as desirable, but I would say leave the few elites to do it, and let them worry about who is clean, then the money spent administrating pointless drug testing (clearly it doesn't work) could be spent where most people actually care about, at grass roots
Also bear in mind that most of this stuff is at the very least unhealthy if taken for long periods, some is downright dangerous to life if taken without proper medical supervision.
Same applies to alcohol, Heroin, coke etc it's all a choice, it all seems a big fuss when athletics is a mass participation sport and really there are only a few elites who will benefit from or ruin it.
Your basic driver doesn't care about emissions, let's be honest, and the testing regime has always been flawed, the emission test of a standard saloon measures as it accelerates from 0-31mph in 23 seconds, anyone admit to driving like that?