If you use the vouch feature much, eventually they take it away from you. Same with upvoting and downvoting, but it all happens silently so most people don't notice.
I didn't see much misuse of vouching in your recent history so I've removed that penalty from your account now. But please make sure that the comments you're vouching for are respecting the site guidelines (https://news.ycombinator.com/newsguidelines.html).
You're keen on reviewing a user's recent history, but provide no corresponding transparency to the user on what you've done.
HN works best with informal systems, not formal ones. The informal contract around transparency is: people are welcome to ask questions and we always answer them, but we don't formally publish a moderation log or anything like that (https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que...).
You're already removing the ability of users to vouch. That frog is boiled.
I'm saying tell them on their user page. Include a line that only they can see which says "can no longer vouch" or similar. That way they know what's happened instead of having to guess what's happened.
I didn’t realize the vouch link doesn’t show up in the main threads.