I am assuming you aren't a moderator based on your last post (apologies if you are), so let me give a few more details on flagging. When a post is flagged, moderators see a red icon appear on the hamburger menu (like blue and green users see on their profile picture). Opening the hamburger menu, you can access the flags system. There, you see what specific post or topic was flagged, by whom, for what, and if the "something else" flag, their message. You then have a few options - agreed, disagree, and defer. With agree/defer there are also some quick tools like delete, hide post and send PM, etc.
It heavily depends on the site and how the moderators work, but from what I've seen discussed here on meta in the past, most flags are deferred unless they are very clearly an issue. Over at Stonehearth, for example. we get flags if a user notices a duplicate topic. We don't "agree" with the flag, even though it is a duplicate, as that hurts the user whose post was flagged. We simply defer the flag, and then merge the topics. The mods at Hopscotch would have to explain how they do things, but I can say with at leat 90% certainty that most users have no "agreed with" flags.