It is worth making a simple basic distinction between facts and opinions.
A fact is a proposition which is constituted by socially agreed terms (i.e. the words in the sentence)and verified by socially agreed means: e.g. Sweden is seeking Julian Assange’s extradition.
Opinion is of two kinds.
First, opinion can pertain to a proposition asserted by someone which cannot be either verified or falsified: e.g. Julian Assange has engaged only in consenting sexual acts. The weight of an opinion which alleges a fact is dependent on the likelihood of the alleged fact being true.
Second, opinion can consist of an “ought premise” e.g. All those who engage only in consenting sexual acts ought not be punished. Ought premises cannot be deemed true or false; they can only be judged consistent or inconsistent with other ought premises.
Ought premises, if universal, can be combined with facts or “opinion facts” to produce new ought premises. For example:
All those who engage only in consenting sexual acts ought not be punished.
Julian Assange has engaged only in consenting sexual acts
Therefore, Julian Assange ought not be punished
All this is very formalistic, but it does provide a means for decoding texts which mix, fact, alleged fact and opinion.