Seasonal flu has also much different spreading. You are spreading it for very short time and then you get clearly sick. Which makes limiting speed much easier.
People in camp (2) don't miss the risk of overwhelmed hospitals. We remember that we were constantly told they were about to be overwhelmed back in April and they never were. Sweden has the lowest ICU capacity in Europe by far, yet never had overwhelmed hospitals despite very visibly turning its back on the policies supposedly required to avoid it. How can this be reconciled with there being genuine risk?
It's apparent when you look at what happened back then that there was no actual risk of anything except running out of ventilators, a problem that was in turn caused by the panic - doctors were told this was a very deadly disease so were putting people on ventilators unnecessarily, partly because ventilation ensures all the air a patient breathes out is filtered, so they thought it was a way to keep hospitals clean. Once doctors realised ventilation was doing more harm than good and the age skews of the patients started to become publicly known, they backed off the ventilator use and there was never any shortage, of either ventilators nor beds.
1) Covid19 is far more deadly, look at all these excess deaths!
2) The IFR is low, about the same as the seasonal flu, so we really didn't need the lockdowns.
Both are half true.
Basically, we have decent herd immunity for existing viruses. Even with an identical IFR, the viruses are acting differently because we lack(ed) any real herd immunity for the new virus - so everyone was getting infected at once, which means everyone getting sick at once and risking overwhelming hospitals (this is the part people in camp 2 miss). On the flip side, because we do have decent herd immunity with existing viruses, either due to prior exposure or vaccine, seasonal flu doesn't spread nearly as far (this is the part people in camp 1 miss). A lot less people getting infected means a lot less people getting sick or dying, which explains the excess death despite the same IFR.