Yes: evidence consistent with an argument establishes a basis, but not necessarily the entire causal proposition

Exactly.

Suppose your proposition is:

Emancipation did not immediately transform racial attitudes.

You find evidence:

Formerly enslaved people encountered widespread hostility after emancipation.

That evidence is consistent with your proposition.

It gives your argument an empirical basis.

But it doesn't automatically prove the entire causal explanation:

centuries of racial hierarchy then emancipation then persistence of racial attitudes.

To establish that causal proposition more strongly, you want evidence connecting the stages.

So there is a hierarchy:

Evidence exists and Evidence supports/is consistent with the claim and

Multiple pieces of evidence strengthen the claim and Evidence may establish the claim with high confidence

And causal claims generally require particularly careful evidence because you need to establish not merely that two things occurred, but that there is a defensible relationship between them.