Link to book: https://archive.org/details/liberalismissin0000sard/page/n5/mode/2up
I think by "liberalism" the author means "classical liberalism" with something of an indifference towards morality: this would allow the "freedom" for things like abortion. He is against this kind of "neutrality" on certain topics: a State that is godless and gives excessive "freedom" to non-Christian religions for example might be absurd, as that would be giving a green light to certain pagan tribes that offer human sacrifice.
Given some of the clearly illustrated excesses of "total religious freedom", these excesses of a "pure" "classical liberalism" however do not exclude Catholics from having a kind of "religious tolerance" towards non-Catholics (Catholic encyclopedia entry on "religious toleration"): https://www.newadvent.org/cathen/14763a.htm
So I think there's a contrast between "unrestricted religious freedom" and a kind of freedom of some "religious tolerance". Frequently I have seen extremes with Vatican 2 modernists advocating perhaps for a kind of religious liberalism condemned in the above book, while I've seen "Catholic traditionalists" deny something of the religious tolerance as suggested in the linked article above.