The answer to your first question is "yes," but nuanced. The reason it can be answered, "yes," is that we need to distinguish between the government and the country. Tremendous problems ensue if we collapse that distinction. Someone might be against the behaviors and policies of those claiming to be the government, yet do so out of love for his country and fellow-people.
You asked if the second statement was a "valid" argument. Strictly speaking it isn't really an argument at all -- a structured set of propositions intended to prove the truth of a contested statement -- so it isn't valid (or invalid). The answer is similar to the first. People attribute or impute different meanings to a nation's flag and how we treat it. Suppose that three different people do not stand for the presentation of the flag. They each might have very different reasons for that. Maybe person 1 is refusing to stand because he believes that law enforcement in the country is acting unjustly. Maybe person 2 is refusing to stand because he thinks the government is oppressive (internally or externally). Maybe person 3 isn't standing because his back hurts.
Even those who stand have different reasons for doing so, with probably most of those being rather arbitrary, uninformed and shallow.
The underlying issue is that people impute different meanings to the flag and to showing it honor. Many then infer that anyone who doesn't act like they do toward the flag holds a belief that is contrary to their own (and is wrong, and should be forced to adopt their belief or at least stop behaving in unpleasant ways). The problem is that both the initial belief and the idea that others should be forced to hold that belief or at least behave thus are usually part of a rats-nest of epistemological, historical, moral and behavioral errors.