I've had it happen to me personally. A National Review writer (who shall remain nameless) who I certainly considered a friend of mine, was so disgusted with my embrace of the alt-right's 'fight back always' position and it's abandonment of civility, that we stopped speaking.
This seemed like high irony a few weeks ago when Charles Murray, an old right/AEI intellectual who had the unmitigated gaul to report facts as he found them instead of twisting reality to suit the liberal narrative, was chased from a University campus by an angry mob of social justice warriors. Suddenly the old right was aghast that handing the left the moral victory without a battle was no longer enough for them, and the alt-right was looking more and more vindicated in it's take.
Well that process has come full circle now, and the source of the most active, vocal criticism of the alt-right's tactics, has been branded by the left as the true source of the Alt-right:
The arguments made are not totally fallacious. NR at one point or another, employed our man Derb, Peter Brimelow, and Bob Weisberg, and continues to publish Victor Davis Hanson's notoriously practical and reality-realist take. Slate feels this is enough to 'blame' them for the alt-right, in spite of their denials.
If only NR could have seen this coming. If only they could have imagined that the left might consider tarring them with the same brush they themselves had been using for several years to tar their own right leaning allies. If only they could have imagined that after they came for the Derb, Peter Brimelow and Bob Weissberg, they would also be coming for them.
Ask not for whom the accusation of racism rings false National Review, it rings false for thee.