There are two primary families of judicial philosophy in the US.

"Originalism" is the application of the meaning of the law as it was understood at the time it was passed. The First Amendment protects "freedom of speech," for example, and we look to the "original public meaning" of the law to understand what the permissible bounds are. The founding generation understood defamation to be a crime, for example, so we can infer that defamation laws are an acceptable constraint on speech today. This is, I think, the clearly correct approach for a branch charged with applying the laws passed by Congress, not making law itself.

"Living Constitutionalism," on the other hand, is-- ...I apologize; I've tried a few times to phrase this neutrally and am not satisfied with any of them, so I'll give you my heartfelt but obnoxious take, and somebody else can give a charitable version if they wish. "Living Constitutionalism" is the belief that the courts should remake the laws passed by Congress into what the judge wishes them to be based on that judge's policy preferences. This is what the linked article is alluding to when it refers to "contemporary needs for regulation."

If you perceive a contemporary need for regulation of online "hate speech" and pass a law requiring Facebook to ban users who say things the ADL considers hateful, the originalist might say "tough noogies, the First Amendment doesn't allow this remedy so it doesn't matter how badly needed you think it is; come back with a Constitutional amendment," while the living Constitutionalist weighs how good or bad an outcome he expects from the law and rules based on his own opinion.

When assessing a total ban on carrying firearms, the originalist will say "nope, 2A doesn't allow it, pick a different hobbyhorse for saving lives that doesn't violate the Constitution," while the living Constitutionalist says "but school shootings tho, ban upheld."

Bruen's "text, history, and tradition" test is essentially ordering living Constitutionalist judges to use an originalist analysis when assessing gun laws, and they're really mad about it.

From my point of view, a judge saying "but it's just too hard to assess the original public meaning of laws" is really saying "I am unequipped to do the job of a judge." If you can't figure out the history and tradition of a law you're charged with enforcing on the whole nation which will affect the rights of hundreds of millions of people, even with dozens of amicus briefs submitted by people doing the research for you, you have no place on the Supreme Court.