Everyday Irrationality: "Not an argument!"

Remember MolyMeme? His catchphrase used to be something along the lines of, "not an argument!" every single time someone made what he perceived to be a non-argument or a simple opinion. I was wondering how productive and logically valid this is, given the fact that while something may appear to be a non-argument, it could be an implicit one.

Example:

Faye: America is institutionally racist.

Frank: Not an argument!

According to RatWiki, Faye's remark could be turned into an argument.

P1: If X happens in America, then America is institutionally racist. (unstated)

P2: X happens in America. (unstated)

C1: America is institutionally racist.

P3: Institutional racism is problematic. (unstated)

C2: America is problematic. (unstated)

Now any of the 3 premises (P#) can be refuted, allowing for a counterargument. Note that pretty much everything there is unstated (enthymemes). However, saying "not an argument!" kills that possibility by dismissing the implicit argument entirely:

P1: That statement is a plain assertion.

P2: Plain assertions are not arguments.

C1: That statement is not an argument.

P3: Non-arguments don't need to be addressed further.

C2: Your statement needs no further addressing.

According to the same source, "not an argument!" is fallacious. But why?

Maybe because it comes across as an Argument from Fallacy - but there is no rejection necessarily of the statement.

Maybe it is a Red Herring, attempting to shift the conversation from the statement itself to whether that statement is an argument or not. But if the statement was not an argument, how could it be a Red Herring? There's no 'reasoning' in the reply.

My question: is Frank guilty of fallacious reasoning here? Is he being uncharitable and not parsing his interlocutor's remark's properly? 

I see no fallacy. I see a problem with "Non-arguments don't need to be addressed further." Someone has made up this "rule." The fact is, productive debate and conversation requires a good-faith effort to understand what the other person means. Most people are not excellent communicators, so excellent communicators need to do the heavy lifting at times to move the conversation along. This requires making the implicit, explicit.

I actually write more about this in my book, Rules of Reason.

Is there a rule that everything one says has to be an argument? As far as I'm aware I can make statements of fact or opinion. 

In a red herring the original statement doesn't have to be an argument, it's the response which is posed as an argument, "your statement is wrong/lacks merit because it isn't an argument", and it is an argument of irrelevance, so is very much a logical fallacy. 

I find that I have to stop and think about this, because we will often say that something isn't an ad hominem as it wasn't in response to an argument, however this is because the definition of ad hominem includes avoiding the argument, not because all logical fallacies have to regard something which is a response to an argument. 

Yes, Frank is guilty of fallacious reasoning, what he should do is ask Faye if she has an argument to support her assertion. 

I think that Frank would be correct. The statement "America is institutionally racist" is an opinion expressed as a statement of fact. There is no if/then antecedent to a consequent. If I said "America is a country in the Northern hemisphere" that is an indisputable fact, by definition. "America is institutionally racist" is in the same format, but is debatable, an unsupported claim, and then arguments can either support or deny the premises, or the conclusions, such as the arguments you follow up with. But the statement itself is not an argument, nor is it a logical fallacy. IMHO