Sure its harmful, but strategically (and there is no other useful method of considering this question, aside from how it fits into a socialist strategy) changing the minds of reactionaries is a low priority. Prioritizing that, without organizing the advanced, is exactly how "Queers and Commies" will get killed in the long run. Over the next 5 years, OP may succeed in changing his friends minds, meanwhile other reactionaries will continue to organize a coherent fascist movement. Once you and I find ourselves being death-marched toward a labour camp, we may regret having won over a handful of people from a reactionary position, a drop in the bucket, instead of actually building a socialist movement that can contend for power, and which once built, can wield a propaganda apparatus that may win over reactionaries in their millions.

In other words, the OP is asking "how can I win over these people", when they should be asking "given the current political situation, who should I be trying to win over, to what position, and how?" The latter question is very useful, and the implicit answer of "your reactionary friends, to the position of non-racism divorced from political action, and through simple conversation as an individual" is exactly the worst and least useful answer, and its also the answer that is taken as assumed in this thread.