I didn't know Zulip or what they did prior to reading this, so I guess it's also contextual. I understand why they would advertize that they didn't change their plan even though Slack did and they are indeed free to post whatever they want on their corporate blog. I would just take it with a grain of salt given the underlying interests.
Oh, I agree completely that the article should be taken with a grain of salt but don’t need a disclaimer. I also didn’t really see anything in the article that made me suspicious.
Do you have any issues with the article?