[ddingus]

In context the user meant:

>>It's a bad argument because it's a bad argument[, not because it came from Cato]

They also imply the bad of the argument is obvious. I do not entirely agree and believe their comment would be improved with just a bit of work.

They did not seriously intend to present a circular fallacy.

Just saying.

[nvm0n2]

It actually is circular as written, especially the part where they claim that the source has a history of bad arguments. As there's no evidence they evaluated the argument at all, we can assume this history is also based on reasoning of the form "it's bad just because" this this boils down to "it's bad just because, just like everything else they say".

Also, you're being too generous to assume there's an unstated justification for why it's is a bad argument. Pretty obvious that there isn't, they just assume anything said by the authors must be bad because tribes.

[cazum]

It can't be circular reasoning because it's not an attempt at reasoning. It's an incredibly common English phrase that means "The argument is independently bad on it's own merit", not an attempt to show a logical incongruity. Others have already explained why the argument does not hold up, I don't need to repeat their work here.

And if we want to be pedantic, "especially the part where they claim that the source has a history of bad arguments" would make my "argument" an ad-hominem fallacy, or perhaps poisoning the well, but not circular reasoning. But again, as I said, the argument is bad independent of the people who made it.

[ddingus]

I don't think I am being generous at all.

That's a common speech pattern and often the intent is basically as I stated.

Cato does, in fact, produce many bad arguments. Now they don't get it all wrong. They have produced good material. That said, I personally do not consider them reputable.