h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

... that is strange (or maybe not so) the 'loyalists' are starting to shoot guns in front of cameras and fight the police, at the very moment the IRA is promising to finally start giving up their guns?

From my understanding, basically the British troops were sent into NI to protect the 'loyalists'. So when they finally started to pull out or at least off the streets, the 'loyalists' felt unprotected and therefore reasoned that if they started the shootings again, the troops would come back.

Even though I am English my views on NI are not the majority of English people's. My belief is that NI should have a vote on whether or not to stay part of Britain. I know this sounds very simplistic, but I am just summarising. If the majority (what this should be I don't know) votes out of Britain then do it.

Why is it Britain is able to hand back Hong Kong, when they can not do the same with Northern Ireland?

The troops actually were sent to N. Ireland to protect the nationalist minority.
Regarding a vote, if only those living in N.I. were polled, the result would be to remain British, if those on the whole of the island were polled, the result would be to become Irish.
You cannot 'hand' N.I. back as it is part of the U.K., not owned by the U.K. e.g. You cannot 'hand back' England, Scotland or Wales.