What is seen as fair is a very subjective question. I would prefer not calling it "fair share" because taxation is very complex and depends hugely on how good you are at gaming the system.
What's the capital gains tax in the US? I seem to distinctly remember it's far lower than a bricklayer's income tax. So, arguably, taxes on bitcoin speculation are not a "fair share" only in the sense that it's still too low.
I think it's fair to say that many people lose perspective when it comes to their wallets.
Paraphrasing Upton Sinclair: It's difficult to get a man to understand something when his portfolio value depends on his not understanding it
CGT is very high in the USA compared to the UK and the rest of the EU - which discourages investment as opposed to buying safe T Bills or Guilts