As far as the Evra/Suarez thing went, if you want people to take your word, it'd be helpful if 3 (IIRC) people at the club didn't change stories/create inconsistencies/get pulled up on half truths etc. If one persons story remains the same and supports their on field reaction, and the others constantly shifts, why would you give the latter the benefit of the doubt?
Only really Comolli's account was inconsistant but he admitted not fully understanding Suarez's Spanish having learnt 'classical Spanish'. Dalglish was accused of trying to cloud Dowd's judgement because he asked "Hadn't he done this before?" about Evra and abuse accusations. Evra hadn't which the report pointed out. It did not point out however that Evra was found to have given unreliable and inconsistant evidence in an invesitigation into abuse (the Chelsea groundsman one if I remember correctly). This is was Dalglish was referring to. It also shows how Evra had a prior understanding of how the investigation would take place.
Evra's account didn't remain the same but changed several times. At the time and on the pitch he only claimed to have been abused once (and several witness statements agree Evra only made an accusation once). Then afterwards in the interview he claimed he had been abused 10 times. Then this was reduced during the actual investiagtion to around five times. There was also inconsistancy with what he claimed Suarez actually said going from 'n****r' to 'black'. Evra was not consistant at all but with everything the FA came down on his side.