Noted journalist Fareed Zakaria explained this phenomenon quite candidly. He begins with an acknowledgment:

And it is worth remembering that the United States still funds guerrilla outfits and opposition groups that are trying to topple the Islamic Republic. Most of these are tiny groups with no chance of success, funded largely to appease right-wing members of Congress. But the Tehran government is able to portray this as an ongoing anti-Iranian campaign.

Notice his use of the word “portray”. The Iranian regime “is able to portray” an ongoing anti-government campaign “as an ongoing anti-Iranian campaign.” Again, the issue isn’t what the facts are, but what the perceptions are. Zakaria then praises President Obama’s response to events in Iran, saying

In this context, President Obama has been right to tread cautiously — for the most part — to extend his moral support to Iranian protesters but not get politically involved.

Remember, it’s not that funding “guerilla outfits and opposition groups that are trying to topple the Islamic Republic” isn’t being “politically involved”. It’s simply that Obama has wisely, and not without success, created the perception of being politically detached. With this as his framework, Zakaria concludes:

Ahmadinejad is also a politician with considerable mass appeal. He knows that accusing the United States and Britain of interference works in some quarters. Our effort should be to make sure that those accusations seem as loony and baseless as possible. Were President Obama to get out in front, vociferously supporting the protests, he would be helping Ahmadinejad’s strategy, not America’s.

So, accusations that the U.S. is interfering in Iran are true. But acknowledging that would be strategically unwise. “Our effort” – and by “our” Zakaria presumably includes journalists like himself – should not be to report the truth (drawing the obvious corollary), but to work to discredit anyone who observes that the long arm of the U.S. has certainly not been withdrawn from Iranian affairs.

There is a vast amount of unverified or, in some cases, verifiably false information floating around, often originating from sources with a clear bias. Tehran Bureau’s use as a primary source someone who is a member of the Mousavi campaign is just one notable example. Information from such sources is then spread around the internet, sometimes with viral effect, without attribution or sourcing and with a completely uncritical eye. This is often on account of the commentator’s own bias, such as the assumption of the teach-in Niknejad participated in that we should express “solidarity” with the “pro-democracy” – that is to say, the “pro-Mousavi” – movement.

Our effort should not be to take sides in an election campaign in a foreign sovereign nation, but rather to make the best effort to be objective and, far from reporting only that information which suits our own personal political ideology, to discern from the available information in an effort to learn the truth.

Regrettably, numerous commentators on recent events in Iran obviously disagree, preferring instead the creed of Fareed Zakaria.