No, it isn’t. It’s either true or false. It’s not a judgement, or a moral statement, it’s a factual statement to be either proved or disproved.
No, they are not racist. The people making the statements, and their reasons for doing so, and the actions they hope to provoke by making those statements, almost certainly are. You may think this is a distinction without a difference, but I don’t.
That those statements are almost certainly false makes it much easier to say that the person uttering them is racist, but an assertion by itself, devoid of context, cannot be.
Not really. “Blacks are subhuman” is a statement that’s either true or false (spoiler alert - it’s false). “Blacks are subhuman so it’s fine to enslave them and treat them worse than animals” is a racist opinion, and a call to racist behaviour. Actually enslaving people because of their skin colour (or for that matter, doing anything else to someone because of their skin colour) is racism.
The act, the opinion, the person, they can be racist. The assertion that something is a certain way is either true or false, and by itself has no moral component, any more that “the sun revolves round the earth” does, to pick an example from further back in time.