From his picture (a picture paints 1000 words, etc) and his lack of mention on normal Chabad sites, I do not think he is a Lubavitcher (Chabad fellow.) His book is not from a normative Orthodox/Chabad standpoint.
We are not ‘opposed’ to, rather we do not enable Reform/liberal/etc Judaism and their tenants. They are Jews (the ones born to Jewish mothers) with all the same rights/obligations/privileges/rewards... even if they don’t accept that yet ;)
Antelman made it clear where he stood on non-Orthodox Judaism. He says Reform Judaism, Haskala, and to a lesser extent, Conservative Judaism, do not keep the 613 commandments, make excuses to not do so because they live in modern society. It thus seems your kind of Chabad is not as strong as his.
But this hasn’t got that much to do with my original post, i.e., your statement about hastening the coming of your Messiah. Just how are you folks doing this, since, according to the Talmud, the world has to be evil for him to come?
By the way, Antelman did not invent all this about Sabbatai, Frank, etc., we’re talking historical events here, most of his book is based on the writings of the late professor at the Hebrew University in Jerusalem, Gershom Sholem. He documents the connecting of his “dots,” I find his documenting of them hard to refute.