Lila - You're right to point out that terrorism is a loaded term that has been used manipulatively in the US. I think a more precise definition should begin by looking at Robert Pape's work.
I am not convinced that terrorism should be equated exclusively with Islam. According to the Southern Poverty Law Center, a wide variety of hate groups operate in the U.S., and many of them are responsible for violent acts.
Maybe it would be better to abandon the categories of "radical" and "terrorist" altogether in favor of something more precise...I will try to work on a better definition of these terms in my next postings.
You correctly argue that Islamophobia is a serious issue in the US. Certainly there is no shortage of shockingly ignorant, hateful propaganda available which seeks to demonize Muslims. Furthermore, the relationship between the government (the Intelligence Community, law enforcement agencies, etc) and American Muslims is problematic. Government surveillance policies tend to alienate Muslim communities, rather than engaging with them and respecting their constitutional rights.
At the same time, I think it's a little disingenuous and too apologetic to focus exclusively on discrimination. I would argue that (domestic) terrorism remains a real security threat in the US. (examples: the failed Times Square bombing attempt, the shoe bomber, hate groups in the US, etc).
The real issue in my mind, which still remains unanswered, is how to address this appropriately. The Brennan Center for Justice at NYU law school published a useful report on discrimination and radicalization in advance of the hearing. Peter T. King would have benefitted immensely from reading it!
Overall, I would argue that the Peter T. King hearing was counterproductive and ineffective in addressing these issues. The hearing was theatrical, emotional, and probably alienated and offended a good number of Muslim Americans. In other words, it did more harm than good, in addressing what I believe is a real security threat -- and again, one that is not exclusively related to Muslims. (That's basically what I meant by, "However, it is unclear whether the hearing was sufficiently productive in addressing the (very real) threat of terrorism.")
I know I still haven't fully responded to your comment, but I hope this helps.