What do you mean?
Either you accept the rankings or you don't - if you don't, fair enough, there is no point talking about it. If you do, you therefore have to accept that there are some issues with press freedom in Poland, relative to the countries above. Simple as that.
No we don't know the exact reasons but since the ranking concerns "press freedom" I think we can all take a wild guess that it just might involve how free (or not) the press is - what do you think?
It doesn't matter what the precise reasons are and it doesn't matter whether or not they are given really if it all amounts to the same thing - less press freedom.
They could, for example, publish whatever they want, but some politicians could sue the newspaper for that, or something.
...therefore, they can't say what they want. Same thing. Unless every paper gets sued every day of the week? No, of course not. So they are restricted.
I don't know why you are making this more complicated when it is very simple.