You’ll see anarchists praising Rosa Luxemburg, who if they had actually read her writings – they would see that she was very clearly one of the “authoritarian” socialists that they rail against so much.
You see them praise the Black Panthers, who were supported financially by the DPRK and aligned themselves with the Juche ideology of Kim Il Sung.
They even praise Thomas Sankara, who purged anarchists and arrested syndicalists.
If these people had succeeded, i have no doubt in my mind that anarchists would call them “tankies,” they would call their experiments “capitalism with a red flag.” And I also have no doubt in my mind that if the October Revolution, Chinese Revolution had been crushed, they would hail Lenin and Mao as proletarian heroes.
If you’re ok with a longish read, I think this lays it out pretty clearly:
https://www.marxists.org/reference/archive/stalin/works/1906/12/x01.htm
The short answer is that anarchists and ML’s don’t have the same goals, and don’t have the same chosen methods to reach them. The only thing we agree on is (roughly) who the enemy is: capitalism.
It goes back over 100 years to the Bakunin/Marx split in the first international. It’s been going for a while!