There are two mods on HN: 'dang and 'sctb. It's not clear to me if you're referring to the two of them in particular or using mod in a more general sense to refer to anyone who is voting or flagging. If the latter, I'd recommend not using the term mod this way on HN. If the former and you believe you have legitimate concerns about their activity (which they're quite open about), I recommend contacting them via the Contact link in the footer and raising the issues you see. In my experience they're very forthcoming.

In my experience, people often have a (completely understandable and human) selective view of downvoting and flagging activity. There's a wide variety of opinions and perspectives on HN and I've seen all of them downvoted or flagged at one time or another, just as I've seen commenters of all persuasions be civil, well-reasoned, and, unfortunately, egregiously trollish and ranty.