That's completely fair, i just think the effect on an indivdual that debating someone on this kind of thing brings can be widely outweighed by the whole process of giving them a platform to preach their ideology? While refusing to engage with someone on an individual level might not help the individual, it also stifles the growth of the ideology much better than discussing it in an open context
You're also always on the back foot, because while they're the aggressor just dumping out claims and you're always playing catch up with real facts and statistics you're also engaging their line of thinking as if it's valid to start with. With something like white nationalism ect, every time you engage with points about why african people aren't genetically inclined to be less smart or do more crimes you're inherently engaging them on the premise that if what they're saying was true, then their racism ect would be justified or acceptable. In that situation even if you give them the publicly humiliating defeat possible, they've still won , at least partially, because the ideology is given a platform and presented as if it would be acceptable under the situation they've presented, and is only stopped from being acceptable because they're wrong about some details
Sorry that this probably isn't as clear and easy to understand as i'd like it to be, but i'm writing it in a rush right now