At the risk of sounding naive, what do the brackets and sunglassses (edit: they're just glasses) mean and how is it anti-semetic?
No idea on the glasses. Maybe a reference to the stereotypical g-man? i.e. he was trying to say that Jews control the government?
Regardless, the parentheses are pretty straightforward.
So it seems to boil down to, "It seems like most of our critics are those upwardly-mobile Jews." Another sad chapter in the descent of WikiLeaks from a journalistic organization that was a reason to hope for humanity into a the Daily Mail for the Kremlin instead of GCHQ.
They really aren't, as the tweets hint they've recently been some sort of an anti-anti-semitism symbol, with lots of jewish people on twitter putting them around their names.