You really ought to update your understanding of (and support for) the 5th and help yourself cherish it
greatly. It has very few parallels in human history.
When someone invokes the 5th, it is as a pleasant reminder that you still are subject to a judicial system that places the burden of proof on the government to prove an innocent defendant guilty. That is how the framers intended it to be--a decisive and enduring departure from bygone days where you were at danger of being forced to incriminate yourself by variously questionable (and sometimes horrific) means.
Citizens invoking the 5th has become in recent decades a vilified action, and this is very dangerous. The reasoning behind a person's invocation of their right against self-incrimination does not matter, and ought not be up to anyone else to judge the merits of. We even instituted Miranda rights to further cement this protection in legal proceedings and the public mind.
I despise the grandstanding and partisanship of American politics. However, when an public official (high-ranking or not; it doesn't matter) invokes the 5th, I take this to mean that the specific question and the implications of answering it, in the particular setting/context in which it is asked causes a person to have reasonable cause and/or justification to "apprehend danger from a direct answer" (Hoffman v. United States). In Grunewald v. United States, the Court held that "one of the Fifth Amendment's basic functions is to protect innocent persons who might otherwise be ensnared by ambiguous circumstances."
In a justice system that holds every person is innocent until proven guilty, that means every person--be they high-ranking official, lowly clerical assistant, or anyone in between.
Universe forbid you ever find yourself accused of a crime, but you will likely find yourself very appreciative of having a constitutional right that affords you the privilege of refusing to testify against yourself in moments you fear direct answers may place you in a dangerous legal position.
Justice requires evidence, not a measurement of your confidence. Let us support uncovering the necessary evidence to understand what has occurred in any given situation, and refrain from prognosticating guilt before then. If we don't, or if we continue to allow the public support of the 5th Amendment to erode further, we may not like the kind of justice we have decades from now.