I'm not sure this is good advice. dang and the rest of the HN braintrust are very opaque about how your own flagging and voting affects your account, and I wouldn't be surprised if flagging or downvoting something like that increases the likelihood of you having some negative weight put on your subsequent votes/flags.
Upvote the wrong things too often and your upvotes will stop voting.
Downvote the wrong things too often and your downvotes will stop working.
Vouch for the wrong things and your vouches will stop working.
Everything you can do here is a privilege contingent on moderator assessment. Go against the flow at your own peril.
I'm just pointing out that it's a weird paranoia to be worried about how your votes, flags, and vouches get interpreted by the mods. "Oh no," you and the other guy say, "they might take away my flagging privileges if I use them." Ok, so out of paranoia you don't use them, which amounts to the same thing. The fear is in your head, get over it.
It isn't something to worry about, but it is something to be aware of.
I don't "worry" about it, as I don't care about karma and almost never flag anything, but most other users care greatly about their internet points (it is orange reddit, after all), and as krapp pointed out, it's long been suspected that using votes, flags, vouches in ways the site algorithmically dislikes or that moderators find adverse results in the equivalent of "hellbanning" of those functions.
For example, I still upvote or vouch comments that I feel were unfairly downvoted or flagged, and at least for vouching, it certainly seems like mine don't work anymore. I guess I vouched too many no-no things, and now I'm on the naughty list.
The fact that dang and the other mods engage in what's effectively a form of low-level gaslighting and deny doing so ought to be reason enough for any HN to dislike them, and yet all I see is fawning praise for the work they do.