"Capitalism is the problem" is a statement so broad an non-specific that it can not be a lie. Certainly any economic system has problems.

Saying that a specific race is inherently evil is a specific factual claim (one that few people actually make).

There's a conversation of some depth to be had here. I think it might simply devolve into "rhetoric is part of a struggle for power", but I am not ready to be that cynical yet.

"Capitalism is the problem". Let's take this as untrue (ironic laughter from the peanut gallery).

Could "capitalism is the problem" be an opinion coming from one person and a blatant lie coming from another?

Is it fundamentally different from "ethnicity X is the problem"?

Is 2x2=7.21 an opinion or a simple absurd? I don't insist the lies I mentioned are as easy to identify. I understand they are easier for some people to believe. But the nature of the difference (as compared to complex, discussable philosophical ideas like "capitalism is a problem") seems to be the same. While abstract philosophical questions of the "life, universe and everything" category can be discussed infinitely and there is no simple right answer, there also are questions to which a simple answer exists, discoverable by any person who would care to exercise some logic (preferably alone, without being afraid to loose an argument).

Pollution is an example of an externality which unregulated <anything>ism fails to address, but since capitalism is the dominant economic model and many capitalists advocate for less regulation, it’s not a dramatic leap of logic to say capitalism is the problem.

The statement "capitalism is the problem" can be saying that capitalism is the problem with respect to a more regulated for of capitalism, Nordic socialism, or even a platonic ideal/imaginary version of communism.

Saying that Ukraine is the aggressor in the current war is a much more specific factual claim (that is absolutely a lie).