All Jews who are keeping torah and mitzvahs must love each other. There us no obligation to love open sinners.
Are you sure?
What about the Gemara: ברור לו מתה יפה – because of ואהבת לרעך כמך for someone who is חייב מיתת בית דין, i.e. ignored עדים והתראה!!!
Are you aware that there is much discussion on the matter?
Why are you so eager to ignore the entire שקלל וטריא and rule out loving sinners, especially in our generation when most sinners are אונסים who must be brought close with love (as the Rambam writes regarding תינוקות שנשבו, see also Chazon Ish יו”ד ח”ב טז)?