Just in case you are genuinely asking, "Correct the Record" is a PAC that pays people to promote Hillary Clinton in a positive light online and also discount any negative online publicity she gets.
By saying that the GP was trying to "correct the record", he's implying that the GGP is a paid shill for Hillary.
Their comment is referencing Correct The Record, a pro-Clinton PAC which, according to a popular but false Reddit rumor, employs commenters to anonymously spread propaganda. See also:
Edit: At the time of this edit, three replies have asked for a citation on "false", so I may as well put it here.
Barrier Breakers 2016, the subject of the original The Daily Beast article that spread the rumor [1], is a real project that spreads messaging (call if propaganda if you want) supporting Clinton. But that messaging is not anonymous or covert. Here are some of their social media accounts:
They post a lot of stuff - the @nobarriers2016 Twitter account has three posts in the last hour. But the accounts are clearly marked as a project of Correct the Record, and the glossy images they share are not even remotely pretending to be grassroots.
According to their spokesperson, they do not have an additional covert operation:
> “Barrier Breakers accounts are always identified as Correct the Record,” spokesperson Elizabeth Shappell said.
That article is a good read in general and explains what they mean by "pushing back":
> In an exchange on May 24, a Twitter user with a bio that reads “Conservative Republican. Trump SUPPORTER. Fox news viewer,” wrote: “Whenever CROOKED HILLARY gets a tough question she either bursts into that blood curdling laughing cackle or starts barking like a dog. #LIAR.” Correct the Record responded with #ImWithHer and a graphic of Clinton with text reading: “She’s the most vetted person on earth. And standing STRONGER than ever.”
(You can find the tweet in question by searching - the response was from the @CTR_DZ account.)
Personally, I consider this approach fairly lame, in line with the brand social media accounts that sometimes show up in my Twitter replies when I complain about the brand. If I got a message from them, I doubt I would feel especially encouraged or interested in resharing their images. But that's a far cry from being immoral, which I think employing anonymous commenters to skew the public debate would be.
Of course, I can't present absolute proof that they are telling the truth about not having an additional covert operation. But there is no evidence whatsoever that they do have one, only baseless speculation about "paid shills", of the sort that's been around forever (I remember when I used to read Slashdot, closer to its prime, and it was Microsoft that supposedly employed an army of them there), combined with a distorted understanding of a real project.
