Which else are hechsherim so complicated, controversial, and politicized?
Because there's such a huge market, and so many gullible people that will just go for the "Mehadrin" label without thinking or questioning what it means.
Add to that Hechsherim that were started for pure political/power reasons (such as the both Hechsherim involved in the Poland cheese fiasco), and you have a recipe for things going downhill.
Details?
Either way, that's a one-off versus an entire country of little to no consensus on what is equal to mainstream US hashgocha.
How do you define "mainstream US Hashgocho"? Would it be from organizations that exist and have a purpose other than just Kashrus? Such as the OU? cRc? (Or other reputable local vaadim such as S. Louis, Denver, Detroit, etc.) Or is it about size and experience (which add Kof-K and OK to the list).
And is the approach "everything in Israel is so politicized and controversial, so I'll just accept them all"? (Which is one of the problems with the Rabanut Mehuderet or Mehadrin, and some others, who will almost blindly accept anything that says badatz or Mehadrin).