Why do you need to view it?
I’m afraid you’ll have to wait until a moderator addresses the flag. They can make it visible again if they disagree with the flagging.
Usually, there is a reason why a post was flagged, and then it can keep the discussion civil and on topic. If basic users are able to view the hidden content, they tend to react to the hidden post.
Since the default rules also say that you should not react to those posts, hiding them is often better. Otherwise, moderators have to look for those reaction posts and delete them too.
When you see bad behavior, don’t reply. It encourages the bad behavior by acknowledging it, consumes your energy, and wastes everyone’s time. Just flag it . If enough flags accrue, action will be taken, either automatically or by moderator intervention.
Of course, you could also ask the staff to change the setting.