Asalaamu alaikum, We should hate the sin but not the sinner. We should do our utmost to try and give guidance, help and support to such a person but by being harsh we will only push them away further and they may even fall into the hands of missionaries with their deceptive dawah.
Rasulallah Sallallahu alaihi wasallam never turned any sinner away who wanted help and guidance for he was more than willing to help them in anyway that he can by showing them kindness and using wisdom and tact when inviting them towards the right path. There wrre even Mushriks at the time who used to taunt and ridicule him but he remained patient and continued to invite them towards the truth and eventually they accepted Islam.
We should try and take every opportunity we can in life to give dawah abd invite others towards the truth and goodness using kbowledge wisdom and tact and being kind gentle and showing good character for harshness and attacking another whether their Muslim or non Muslim will only bring their defences up and will not benefit them in anyway. It maybe that if we invite tgem in the best way possible like Allah tells us to in the Quran then Allah may guide them and surely our speech will be pleasing to Allah and at the same time we will gain immense rewards of every good action they do.
So in conclusion we should use the approach of our Prophet Sallallahu alaihi wasallam and be gentle with them and show them kindness when inviting them towards goodness using wisdom and tact but we should not hate anyone because it maybe that the one we hate becomes the most beloved in the eyes of Allah.
And Allah knows best in all matters