The Federalist Society is, generally speaking, an ultra-conservative interest group that has been the driving force behind Republican judicial nominations in the US for the past several decades.

I do not think that there is anything inherently wrong with textualism or originalism, nor do I think exerting pressure on Republican lawmakers to support their judicial ideology is necessarily wrong (lobbying in general is a feature, not a bug) but, especially in the past few years, FedSoc has taken a decidedly ideological and more explicitly political course. For example, for most of their history, you could at least say they were serious lawyers who adhered to the mores of that group, but now, when it comes to election denial, for example, they tolerate their members making frivolous lawsuits denying election results.
They are also the forum for, e.g., Justice Alito yelling at clouds about how he doesn't like how irreligious and liberal society is becoming.

They are not all like that; I was friends with some FedSoc people in law school, and many of them are more normal conservatives who don't like Trump and the turn that conservative American politics has taken, but the group as a whole has devolved from something with serious intellectual credibility to the place where all the right-wingers in law school congregate (irrespective of how much they actually care about originalism and textualism beyond the fact that such interpretive philosophies yield results they like), which has diluted its brand.

Notable in this specific context is that it's not uncommon for FedSoc enjoyers to want to almost totally dismantle the Federal government and prevent it from doing anything, and of course Covid restrictions were a particular target of their ire. Basically, they would rather everyone die free than accept that society may restrict individual freedom for the common good/to save lives. I took a class in law school with a pretty prominent FedSoc professor, Phillip Hamburger. He's a really nice and smart guy, and I generally like him, but his views on the administrative state and his non-profit's litigation on stuff like Covid restrictions are simply extreme, unnuanced, and irresponsible. And this author, IIRC, is someone who joined his org specifically to work on Covid stuff. So this is not an article penned by someone who is genuinely weighing evidence, or who truly understands different sides of the debate here. It's like an op-ed by a candidate for political office pointing out flaws in their opponent's positions lol

So I would not take what they say about Covid as being spoken in good faith even though I have certain points of agreement with them in their general judicial philosophy and certain legal opinions. Like, you would be unlikely to get Bernie Sanders or Elizabeth Warren, as much as I generally like them, to admit the demonstrable superiority of American capitalism in producing meaningfully strong and innovative companies vis-a-vis, e.g., Europe, or admit there is something beneficial about that. Similarly, you will probably never get this kind of FedSoc guy to admit that society should be able to restrain individual freedom in order to mitigate some destructive risk. He has no interest in weighing the pros and cons. He knows the outcome he wants.

Of course, this is hypocritical because FedSoc people were one of the driving forces behind overturning Roe, and thus are a-okay with the government restraining abortions even when an abortion would save a woman's life--yet they are not ok with mask mandates. So it's difficult to take them seriously at this point.

FedSoc people know better than to like Trump, for example, but they cozied up to him to get their judges in place. And it worked; one of the only areas of permanent success from the Trump Administration (in the sense of "he achieved his party's objectives") is the stacking of the Federal judiciary with conservative judges, in particular, of course, SCOTUS. It was an important presidency because of how many nominations there were to be made at that time, so that's how FedSoc viewed the stakes. But of course, they ignored their better angels to get this result, which could also be said of people like McConnell too.

I do not know that there is an analogue in Europe (assuming that's where you are).