I think his point is that there is little logical reason to differentiate between a Tzeduki and a Conservative for this.
You mean for shechita?
That is ridiculous. The tzedukim believed they were required to shecht the same way we do it. The conservative don’t. So that is a pretty good reason to differentiate.
Re the halacha being to trust tzeduki shechita: what changed? We no longer trust shechita of people with those de’os.
They changed. The ones who still “hold” of that deah are a bunch of kookoos.