This is crap and a lazy claim. In the US, for instance, fascist tactics from democrats appear to originate from neo-liberals (Clinton, Obama) rather than leftists (Warren, Sanders, Stein).
If you squint, you can see that capitalism and regulatory capture have always been core to fascism. Neither are leftist values at all.
If you're obliquely referring to, err, recent "PC" culture, that seems to share a lot more with puritan culture than a form of government.
What about the trend of shutting down or outright physically attacking speakers at collage campuses lately? I'd call that using violence to suppress politically opposing opinions, and it's something that you will exclusively see leftist do against speakers they disagree with. Or concepts such as the Progressive Stack, where people are discriminated against based on race and gender, in other words literally racism. Or any of the other crazy ideas coming out of social justice these days.
If you're interested in developing that line of thought, I suggest reading Liberal Fascism: The Secret History of the American Left, From Mussolini to the Politics of Meaning which is well researched and deeply insightful.
I think this is more an issue with the lack of nuance in a Left-Right political spectrum. The more axis and metrics used to define a political position the easier it tends to be to to compare it to other positions.
