Attacking the Source
Technically, these are forms of the Ad Hominem attack, latin for "to the man", english for, "Waaah! Your point is beyond my capability to respond". This is where an argument is rebutted by attacking the character, motive, or other attribute of the source or person making a point, rather than attacking the substance of the argument itself.
The reason this is a logical fallacy, is because you can take the most vile person, or the most vile source, and that doesn't mean they're wrong on the topic mentioned. Many vile socialists (Mao, Hitler, Lenin, Pol Pot, Stalin, Castro, Bernie Sanders), had many topics or quotes that were true, even if overall as humans they had vile and detestable records. Hitler once said that momentum = mass x velocity -- are you going to claim it was wrong, just because Hitler said it?
The same applies to sources, only more so. HuffPo is one of the first dumpster fires of "New Journalism" on the web. A place where anyone who was famous could get a blog to opine on shit that was well above their intellectual carrying capacity, and much of the rest was tripe about fashion or celebrity gawking, or stuff that brought the IQ of readers down by participating. That being said, amongst the vast waste of authors, they have a couple intelligent writers -- and even amongst their dimmest bulbs, they occasionally pen a good piece, or at least have a good point.
Writing off the source, like those that say, "that was on Faux News", shows that the person is a dumb, close-minded, bigot. FoxNews is the CNN of the right (just as biased, and often as wrong), but that doesn't mean they don't get things right too. Sure, Sean Hannity is a partisan hack like Rachael Maddow (if she had a triple digit IQ, and could think of cause and effect) -- but that doesn't mean everything on Fox is bad, or that every story is wrong, and more than Maddow doesn't occasionally trip over a valid point. CNN may be the mother of Fake News, with a deluge of hand wringing over later debunked stories, discredited authors, and landslide of bias -- but they do get things right too. And not just on things I agree with. (Though usually, that were later debunked were things that I disagreed with them on).
Consider the source vs ignore it because of the source
There's a huge difference between words of caution: "this is a biased source, so you probably don't have the full story", and the far broader brush, and heavier mallet of, "ignore it because of the source". The former is very valid. The latter makes the commenter a laughing stock.
So "Consider the Source" is valid.... but you should be doubting the source, whether you like the source or not. That's called critical thinking, or skepticism. Even the bias of putting added scrutiny on sources that are often wrong, isn't an ad hominem fallacy. A lot of it is intent and degree. Every source is biased. Every source makes mistakes. But if it's a source like the NYT, WaPo, or CNN with a long history of bias and getting it wrong, then saying, "consider the source" as in, consider their bias and their record, is a great cautionary warning. But it doesn't refute an argument by itself. Generally, it helps if you have a lot more than that to go, because that alone is just bias/bigotry against that source. (Broad brushing that because they're wrong so often in the past, they must be wrong now too).
What's doubly ironic, is often when people attack the source, they're too ego-bound to think through what they're saying.
"Who is iGeek?" Or, "who is this Ari guy?", is not just an attack on me, or iGeek, but what is said (or that's how they're trying to use it). But I have a habit (especially on this site) of sourcing the shit out of what I'm saying. 10, 20, or 50 citations for what I'm saying, isn't that unusual. So they're actually not questioning me, when they say that -- they're questioning all the publications that I'm citing in that point.
Now sometimes, that's just another fallacy. As my cites are places they don't like -- but again, just because they don't like them, or they're biased sources, doesn't make them or their points on this topic wrong. But often, I'm citing sources that bias THEIR way. I use many left leaning sources to prove my point, as well as getting to the root peer-reviewed scientific papers on topics.
Many times, I'll torture them a little... "what is wrong". Try to get them to find a point that they disagree with -- then quote the citations. "So you think the NYT is not credible?", "Do you disagree with the peer reviewed scientific study? Based on what?", and so on.
If they're going to lower the argument into attacking the source, I'm going to try to get them to raise their game and either concede the point that they don't actually disagree with the sources, or at least take a stand on which source they disagree with and why.
Of course we get back to the problem that just because you like a source, doesn't mean it is never wrong. But if you attack a piece broadly, you're attacking it's sources broadly too. Which is why I try to get people to get very specific on what is wrong, and why. Many just get frustrated and find an excuse to go away and block me without admitting to themselves (or others) why the disagree. But that's fine too. If they can't handle that kind of sparring and intellectual exploration, then mere facts I present weren't going to persuade them when they have feelings. And their feelings certainly wasn't going to persuade me, when I have facts that I'm paying attention to.