most people aren't interested in sub 60 FPS, especially if it's at 1080p

Hate to say it but this is a city building sim. Above 60fps would be amazing, but Cities Skylines 1 was already known for being... not great for frame pacing or frame rates.

Obviously more is better, but you can look at any similar game and get fairly understanding "oh only 37 FPS in CS1/CIV6/Rise of Industry/Urbek City Builder/Satisfactory/Dyson Sphere Program, that's pretty solid." The only (similar-ish) game I can think of that actually has never had bad performance is "Per Aspera", but every single other one mentioned, I have had performance "desires/issues." I could also throw rimworld and dwarf fortress in there but those are different enough to be questionably relevant, but those too have performance problems at different points in time.

That being said, it does not sound like the Devs intentionally hid this info, the content creators did mention early on there were performance issues and that Paradox was aiming to have them resolved. If there was any intentional hiding, it would be probably from Paradox as the publisher, but they seem to be relatively open this time around in regards to information.

TLDR: Low fps in genre ain't that surprising, most are used to it. Obviously more is better, but they seem to be at least intent on addressing it, unlike some other devs.