[Sabertooth]

Since when, is the mere act of speaking up in one's own defense not allowed in the US?

Luis, that's not what happened. Khaled Saffuri used his access with this Administration and attempted to intervene in an ongoing terror investigation of the Safa Trust, a donor to his Islamic Institute. He wasn't speaking up in his own defense.

Bush obviously had no knowledge of the meeting, but that doesn't make Saffuri's attempt to influence the investigation less problematic.

[Luis Gonzalez]

OK, so he was there to speak in behalf of others being investigated.

Note the word "investigated". An investigation usually includes the gathering of information from all sorts of different sources in order to arrive at a conclusion.

If you exclude sources arguing in behalf of the people or group being investigated, or providing facts contrary to the accusations and/or incidents in question, it stops being an investigation, and becomes a witch hunt.