fruit contains mostly water and some fiber. there is little sugar in it. and those sugars are completely natural, not refined, and their glycemic load is very low.
humans evolved consuming primarily fruits, it is in every religious book (Adam and Eve and the apple etc), so no clue who told you fruit is bad. it is the easiest thing to digest of any food out there. we see a lot of dieticians and doctors steering people from fruit out of ignorance. fun fact: when you consume proteins they go through glucogenisis, so they turn into sugar in the body anyway. so it is hypocritical for people to think that fruit is bad but meat is good due to the carb and sugar number