For those ones we just say that they are, since we need those for the argument to hold logically. So we stipulate that for those properties there is no confusion, and they are perfect. You are totally allowed to say “hmm, seems suspicious,” but by the definition of these properties, there’s nothing contradictory about asserting that these properties are perfect.
But for a property like “is omniscient” or whatever, we could be more unsure. Since maybe “being omniscient” implies you also “know what it’s like to kick a baby.” And so it implies that you have a property that is not perfect, for example.
For those ones we just say that they are, since we need those for the argument to hold logically. So we stipulate that for those properties there is no confusion, and they are perfect. You are totally allowed to say “hmm, seems suspicious,” but by the definition of these properties, there’s nothing contradictory about asserting that these properties are perfect.
But for a property like “is omniscient” or whatever, we could be more unsure. Since maybe “being omniscient” implies you also “know what it’s like to kick a baby.” And so it implies that you have a property that is not perfect, for example.