Using the word obvious isn't an ad hominem, unless you're for some reason taking it as a personal attack.
In a prior post, you said, "Ad hominem arguments are one of the main tools of cointel (as well as the straw man argument)."
This is akin to saying, "Drinking water is one of the main requirements of the violent psychopath."
Straw man arguments and ad hominem arguments are the main tools of a much larger body of people than cointel pro agents, namely 98% of people posting on forums on the internet. Do you see how your argument makes no logistical sense and is an implied ad hominem in and of itself?
Just like saying it's obvious that 2 + 2 equals four, when you make the point that it's obvious, you're saying that most average people would find it obvious. Don't take and claim the argument is something it's not just because you're feeling defensive. Not everything is a personal attack, and ad hominems don't encompass all personal attacks, they're really only applicable insofar as they're being used to toss out an argument. For instance:
Ad hominem - jd925 is an idiot, therefore you shouldn't believe what he says.
Not ad hominem - jd925 is wrong about ad hominems, as he has failed to take into account how their usage qualifies them as a fallacy, not a part of speech. jd925 is an idiot for trying to classify every sentence that attacks him as an ad hominem.
Do you see the difference? In one I'm trying to get your argument tossed on the basis of your idiocy. This is an ad hominem. You'll note it on the wikipedia page you've posted. "Ad hominem is an attack on the person, not the person's arguments, though mere verbal abuse in the absence of an argument, however, is not ad hominem nor any kind of logical fallacy."