The argument is not that "forgetting" is fundamentally bad - it's that the choice of what to leave out can be meaningful. Han unification removes some amount of distinction between things that are meaningfully different and instead relies on additional metadata to reconstruct that. What are the wider social consequences of that? I don't know, but it's not clear that those involved in making the decision do either.
The fundamental point here is that hacker culture has often made decisions without considering the effect they have on non-hackers (or even hackers of different backgrounds), and as a result those decisions may result in abstractions that "forget" meaningful data. Uncompressed digitisation of audio is a case where it's unlikely that the difference is important in any way, but there are plenty of examples given where it is. The suggestion that having more information can help us make better decisions shouldn't be controversial.
By the way, people seem to think Han unification was forced on CJK users by evil white people from Unicode (there was an article like this in modelviewculture once), but it was contributed by the relevant Asian governments.
And of course China already made much larger changes in real life by creating Simplified Chinese.
The fundamental point here is that hacker culture has often made decisions without considering the effect they have on non-hackers (or even hackers of different backgrounds), and as a result those decisions may result in abstractions that "forget" meaningful data. Uncompressed digitisation of audio is a case where it's unlikely that the difference is important in any way, but there are plenty of examples given where it is. The suggestion that having more information can help us make better decisions shouldn't be controversial.