I don't think that this is a particular form of exceptionalism, beyond the US having a longer tradition of widespread, retail-owned shares, and law-making around that fact.
But sometimes I wonder when people are criticising the US as a culture, they're often choosing as the baseline that should be respected standards that were also defined in a US cultural context. What this sometimes means is that in internal US culture these points are seen as something that is heavily discussed, because there was a point where it was democratically decided and therefore could be undecided in the same way, like corporate personhood, or money-as-speech. In the case of the criminalization "insider trading", there is lively debate about whether this is actually a "good thing". That can sound horrific externally, because of course insider trading is a bad thing. But someone decided to make that a bad thing, and -- for historical accident reasons -- the edges of that debate was largely defined within the US.
(This is mostly just barely-informed speculation: sometimes issues like this emerge in international fora, or start in another culture and quickly spread. But the cultural and financial dominance of the US in the last century or so really makes these things often a point of debate in American terms, and a fixed point elsewhere. I speak here as an immigrant to the US and also someone who is dipped in global policy work, rather than someone who is stating this as a good or a bad thing.)
