It only compromises your integrity if you're claiming that you're not doing it -- in my experience, most people microdosing LSD don't brag about how they're not doping. Lance Armstrong, however....
I personally am on the fence about LSD microdosing (and relatedly, most nootropics). There's evidence on both sides and much of it likely comes down to personal psychology and physiology.
I think we are going to have to accept the future where unenhanced humans are (largely) obsolete at the top (say, 0.1% or 0.01%), though: if it's not drugs, then it'll be cybernetic implants.
I think we might actually agree at a deeper level, and disagree how to address it: you seem to be interested in regulating the actions of people to prevent a tragedy of the commons situation, while I think we need to change the fundamentally exploitative economic structure that's precipitating the tragedy; I think both of us are more concerned with the coercive aspect of the problem than that people are doping.
I don't want people to be desparate for an edge, but I also think people have a fundamental right to burn brighter for less time if they want to. But I don't like the ratcheting of that becoming necessary for survival any more than you do.