Discussing the bad argument that you should believe that determinism is false, because if determinism is true, you can't determine whether or not you believe in determinism. So you should assume it is false, since only in that case can you do yourself any benefit or any harm.
Among other things I note that people are convinced by the bad argument for the same reason they are convinced to smoke in the Smoking Lesion.
It certainly isn't meaningless, and there are several possible meanings. You mention one of them yourself.
Also, all words are poorly defined, since we define words by other words (which are themselves subject to the same problem) or by pointing to things, which is a poor way to define things.