"A foreign government could, for example, compel a service to out people sharing disfavored political speech. That's no hypothetical: WeChat, the popular Chinese messaging app, already uses content matching to identify dissident material. India enacted rules this year that could require pre-screening content critical of government policy. Russia recently fined Google, Facebook and Twitter for not removing pro-democracy protest materials."
Without taking a side in this, none of those things in the above warning could be forced on Apple with what Apple says they're doing. Apple has a list of hashes and they're checking images uploaded to iCloud to see if they match that hash. WeChat's content matching would require text content analysis — totally different. The India example appears to be the same kind of thing (or maybe a requirement for human pre-screening, which is more different still). And the Russia example is where Russia identified posts or pictures and demanded they be removed; which is absolutely not the same thing.
So... this article seems to be people urging Apple not to proceed with its plans, based on warnings that have little to do with what Apple is actually doing.