Not entirely sure why you're being downvoted—maybe some are reading your list of groups, seeing their own, and saying, "well they were right up until that part," and got offended—but you are correct that illiberalism exists on all sides of the political spectrum.

And of course when it does, the now-illiberal faction rationalizes it with some manner of, "liberalism, except when..."

The problem with liberalism is that—while it is the most sane mode of structural organization—it is extremely brittle in the face of illiberalism.

Liberalism—and its ancestors/influences—never ate itself, unlike illiberalism. But it does always fall to barbarism. It's like having an argument with an insane person: you may be right, but you'll never win that fight.

That is a seriously concerning weakness, because when liberalism is threatened, the default modes of self preservation are either: roll over and get beaten (as a matter of principal) or reject some (or all) liberalism in order to fight back. In either case, liberalism goes away.

I'm not sure that anyone has ever come up with a reasonable defense. (And maybe there is none.) Humanity seems to prefer pendula. The grass is always greener...