These are not your objections to an argument you read. Toulmin analysis doesn't call for you to get involved in the argument, just analyze it. Rather, these are objections that the writer feels opponents on the other side of the argument might make. Usually, these are included in arguments so that writers can get to rebuttal or refutation. (Gentle reminder: writers don't help their overall credibility by misstating their opponents' objections or ignoring major objections in favor of minor objections that are easier to rebut.)