You make a good point here and I'll go on to add...

I'm a relatively new lurker, still working through the Sequences.

This (usually, but depending on the engagement level) does constitute deliberate practice. It's directed and requires intense construction of new mental concepts and ways of thinking. In fact, I would say that even for people who have read the sequences previously could still be executing deliberate practice by engaging with them again. It must be 'engage' rather than skim and obviously doesn't apply indefinitely. Practice must move to a new area once a skill is mastered to an acceptable level. When it comes to learning stuff that means not just 'kinda get it' but also not having understood it enough that going over it more isn't even effortful.