...if dissidents were killed by the special forces...

The thing is that "the special forces" in Northern Ireland are still liable to be seen as the people who in the past have not worried too much about restricting their killing to "dissidents".

That is why deploying them tends to be seen as provocative - and as playing into the hands of those who would like to fire up the war once again. Those whose intention, in Gerry Adams' words is "To bring British soldiers back onto the streets. They want to destroy the progress of recent times and to plunge Ireland back into conflict."