it is Strange for me how you regularly confuse the distinction between rejection of the ideology and rejection of the person who might be a follower of that ideology. The Chazon Ish famously wrote (YD 1) that in our generation we have to judge each person individually and you can’t simply go after titles. However that certainly doesn’t mean that the majority of anybody falls on one side of that line or the other. It is certainly possible, acourding to the Chazon Ish, that all of Reform and Conservative and Catholic and Muslim and Modern Orthodox and dati lumi and 4/5 of the haredi world are all not part of “Amisecha” because of the avoda zureh you are referring too.
Many reform People think they are part the Jewish nation and if you would tell them That according to Torah followers of Reform heresy are not part of the Jewish people They would be incredulous and say are you really going to be pusel 80% of the Jewish world?! So too the Catholics would say you have to go after the majority and look the majority of the world 99% accept the Catholic version of Judaism! so how could it be the Catholics are all wrong?! But of course the truth is that the Torah is not a numbers game. There’s Torah and – lehavdil – there’s heresy. It is certainly possible that there is only a small “minyan mitzimtzen” of kosher Yidden alive today. So too the opposite extreme. It could be that in Bais Din shel Ma’aluh half the Reform population is nebuch tinik shenishbuh that will get their rewards as Jews. None of this changes the Torah. None of this changes the rules and axioms how we basar v’dum are supposed to relate to kefira and kofrim in either direction.
It’s not our business to know the actual din v’chesbon of anyone, since we can never know what’s in a persons heart. But we must point out heresy when it shows itself and we must reject with two hands every false moshiach or distortion of Torah such as Reform, Catholic, or Dati Leumi.