Bloggers should be able to speak out against radicals, as this helps to spread word of what it is really like. If everyone just kept quiet, nothing would change. This is true in all walks of life, not just specific to this issue. Raising awareness causes great changes in life.
No, I do not think that bloggers in the Middle East should stop speaking against radicals because bloggers are criticizing the evil beliefs of these radical individuals to ensure that such beliefs don't become normal in their communities. These bloggers are heroes and are risking their lives and safety to speak out against injustice and evil thought.
The World cannot defeat radical terrorists groups in the Middle East with military power alone. Yes, it's very dangerous for bloggers to speak out against these radicals, and doing so can often lead to death. However, winning the fight against radical terrorists groups is going to take changing the hearts and minds of those that might be interested in joining them. Therefore, brave bloggers that are willing to take on these groups with sound, rational arguments against their brutality have the best chance at turning people against these barbaric groups.
Bloggers can help others gain the conviction to act against radicals who endanger their communities. That said, bloggers should work whenever possible to preserve their privacy and safety. Use private VPNs so that their locations cannot be discovered. Do not share information that can be used to identify them. These together can keep them safe.