I did read that. The description of Republicans you're referring to was not written by the conservative Democrats of the day, it was written by a modern and controversial historian who you likely aren't interested in citing, and the author of that article states he "identifies 19th century Republicans as liberals or radicals". Note, the "or". I'll give you that there is an amount of vagueness in that choice of words to infer that those are supposed to be synonyms , but that is an incorrect inference, the liberal and radical groups were opposing factions. Calling those the same would be like saying Biden is conservative and AOC is socialist, so the Democrats today are conservative socialists. I know it's a little semantic thing, but smushing those words together like that makes nonsense.