Kiwi Farms is not against the doxing of public government officials, Kiwi Farms is against the potential legislation that can come from this.
Currently doxing isn't seen as a federal offense (there's no federal laws that addresses doxing in of itself) but some states both blue and red leaning (like California and Missouri) have already made doxing a crime (it's either seen as a misdemeanor or a felony depending on the state). This may finally motivate the federal government to try to pass legislation that addresses the act of doxing.
But some midwit would say, "But isn't doxing free speech?" While publicly available information is protected by the First Amendment, there's still some things that are not seen as protected speech such as stalking, trespassing, vandalism, death threats, swatting and other things that can be seen as malicious behavior or intent (criminal harassment as far to my knowledge has never been seen as protected speech in American legal history).
Most importantly, the federal government can make the argument against doxing with malicious intent of any kind by pulling out the classic 'National Security' card just like what they did with the Tiktok ban law (where the Supreme Court sided with the federal government in the Tiktok ban case and I imagine the Supreme Court won't object to legislation that targets some forms of malicious behavior online that can be seen as a national security risk).
What Kiwi Farms (and other online communities just like them) really fears is that they may be labeled as enemies of the state soon should such legislation becomes reality. It doesn't help that Elon Musk (the head of DOGE) has put it on record that he doesn't consider doxing as free speech ever since he bought out Twitter; so doxing is probably next on the chopping block for the American government sooner or later. If such a thing were to happen where an anti-doxing bill were to become law, then websites like Kiwi Farms may be forced to either take down said content related to real life individuals (in this case the lolcows being featured) or the websites in question have to shut down due to the legal liabilities.