This has more to do with the relations between Suuni and Shiite Muslims than anything. From the looks of the report, the staff arrested were Bahraini, and likely Shiite, as 90% of the Bahraini population is. I can guarantee you that none of them were American.
Also, it looks very likely they were using the hospital as a cover area to assist in staging Shiite uprisings, which in my mind is a terrible thing to do, considering you put your patients at risk by bringing politics into a protected area like the hospital.
I am not trying to make excuses for the Suuni ruling regime, as they took a very hardline approach and went into the situation cracking skulls, however the Shiite's knew this was a possibility when they began their uprising. Also, as I mentioned earlier, the hospital is not the place to be organizing these activities, especially if you are doing so knowing that it could be inviting violence into the facility.
The medics were not arrested for treating patients, they were arrested for participating in a protest, which in that country is illegal. There were many more medics who treated patients on both sides of the skirmish who remain out of jail. I also find the fact that the report says the medics and other healthcare workers were refusing to treat members of the military or other government related employees unless they supported the uprising a bit unsettling.
Anyway, I know my comment has the potential to start quite a sitr. These are just my thoughts and opinions having been in that region for a short amount of time, and having traveled to Bahrain a few times. I would also like to point out that Saudi Arabia and Bahrain are dramatically different...while the royal families are closely related, the demographics of the country and the potential for unrest couldn't be farther apart. Bahrain is one of the only countries other than Iran that has a majority Shiite Muslim population, and they have a Suuni ruling family. This is where the issue lies. KSA has a majority Suuni population, a Suuni royal family, and a King who had been doing quite a bit to begin the separation of the church and the state.
Unfortunately that region will never have peace. T. E. Lawrence put it best...the Arab people will remain fractured and embroiled in conflict as long as they maintain their tribal ways and hold tribal grudges. I see no sign of this changing in the near future.