I think the claims that Bahrain is "back to normal" is pretty delusional. There's some very clear reports that the violence still exists. Just smells like they are papering over the cracks.
Should Sports and politics get involved? Well, they are involved, there's no choice in the matter, our government has a sports minister and a sports dept and I'm guessing most countries will, certainly in Europe.
If we're saying that we won't race in a country that has had severe political issues, then that could be a tricky precedent to set, as others have mentioned, you could apply it to various countries.
Ultimately, I think Sport has to be (barring some instances, like the racial quota system in place in South African cricket) as politically free as possible, but if there's a safety issue, they shouldn't be there. Then again, Brazil has had some instances over the years with F1 staff being targeted, etc.
Should it go ahead? Ask the teams and drivers, they're the guys we should care about.