If you think it's illegal you must think he's broken a law. Which law?

How would I know, but I read that the police are considering a prosecution.

If you think that the porn was not illegal, you must be agreeing with the policeman.

No.

He's the only person who's said that the porn was legal.

He is also the only person claiming it existed at all.
There is no-one anywhere claiming it was not legal!

Do you think the copper would have been right not to disclose at that point what he knew (and which we, as yet, don't know the details of)? Questions, questions!

No question. It was wrong. The police chief states that.

Looking at legal porn is something almost everyone has done so it is not relevant to the other allegation at all.
It is not evidence of any kind of criminality.

You are still banging on about nothing.
Just a politically motivated witch hunt.