I wouldn't have unfrozen it without a reason.
Then what was the reason? The room was dead for two weeks, was auto-frozen, nobody cared for 3 days, you unfroze it, and that was it. I'm not seeing the reason for unfreezing it. In particular since, as you said in a comment
it would be nice to have this because it doesn't involve me having to actually enter the room and post a message (not that it's hard) and can be handled from the access tab.
not even you really cared about the room. If you're trying to revive a community's conversation, that's great, but just unfreezing a dead room won't get you there. After all, anyone with 100 rep could just create a new room if the existing site room(s) didn't fit what they want to talk about.
Posting a random message to delay the freezing is not always sufficient, if my memory serves me right (I don't have an example off hand)
Such an example would be important here though, because it should indeed be sufficient.
but I shouldn't have to do that.
That's true, usually you shouldn't have to do that, because unfreezing a room really has no point if you do it just for the purpose of unfreezing it. If a room has been dead for two weeks (!), that means nobody cares about the room, and unless you have reason to suspect that the room may get some activity again, I don't see why you would unfreeze it.
In the case, however, that you really think a room should be unfrozen despite there being nothing to talk about at the moment, there is an obvious way to achieve that, as you said yourself.
You could also consider getting Community ♦ to raise a flag if the main room is frozen
There is no such thing as a "main room". If, at all, there's the most-active room for the given site, which, in case of DSP.se, is this one. The system makes sure that there's at least one (general purpose, i.e. public and not "discussion between" etc.) room for any given site.
So when a user comes from a freshly launched site, we make sure to auto-create a room, so that chat.se is not "empty" as far as that site goes, and the last remaining room from a site will never be auto-frozen.
If, however, the community starts gathering in a different room, and neglects the auto-created one (which is precisely the case for DSP), we have no problem with culling the latter.
Now, from the room title I guess that in the case of DSP, the active room is actually a special-purpose room (I haven't checked the transcript closely to confirm that it's actually used like that), but unlike the original room, it's also a place where the community does, in fact, show up.
It may very well happen that such a special-purpose room turns into the general room for the site, or that a general room is at some point "forked" off the special-purpose room, or it may just be the case that only those users interested in the particular special topic actually care about chat in the first place. So be it.
Lastly, even if we did what you suggested – a room that only consists of "this room has been auto-frozen" / "yoda has unfrozen this room" every two weeks is not very inviting. On the other hand, if you use the message you're "forced" to post (in order to keep the room from being re-frozen) to try to restart a conversation in the room, more power to you – but just clicking unfreeze surely won't achieve that.