Glenn Greenwald, for The Guardian, writes about the response to Margaret Thatcher’s death:

This demand for respectful silence in the wake of a public figure’s death is not just misguided but dangerous. That one should not speak ill of the dead is arguably appropriate when a private person dies, but it is wildly inappropriate for the death of a controversial public figure, particularly one who wielded significant influence and political power. “Respecting the grief” of Thatcher’s family members is appropriate if one is friends with them or attends a wake they organize, but the protocols are fundamentally different when it comes to public discourse about the person’s life and political acts.

In short: we’re applying the etiquette of our personal relationships to politics.  This is not uncommon, of course: people have a warped perception of how our nation operates (say, related to the debt) because they look at it through the prism of their personal finances.