One of the things I constantly run into (in anarchist circles, particularly as a school abolitionist, and in reading history) is discussion of age.
Unfortunately, there are still far too many people who are skeptical of Youth Liberation (many often misrepresent it as "ignoring the needs of growing children" rather than a more accurate understanding of it being "caring for children while acknowledging their agency and autonomy").
There are still far too many people sharing the ideals of "it's creepy if children talk to any adults except these few" (implying that all adults except those have bad motives, which harms our understanding of predators and predatory relationships) or "children *must* be in school because they won't learn in any other way" (neglecting what we know about how people learn). And they do this without even pausing to consider the ramifications.
But another often overlooked thing? Is the lack of being able to pass down and build upon a shared movement.