I been saying this for weeks..once they lifted restrictions, people acted like it was over and they could relax.
This government was too quick to lift restrictions, did a poor job managing what needs to be reopened first and the messaging made it seem like life was back to normal when it shouldn't be.
What's the alternative though? Indefinite lockdowns? People have started to discount every trade-off associated with them. Lost education, lost revenue, mental health impacts etc.
Goverments thankfully stepped in for people who've lost jobs, but I think many people who've adjusted easily because they can work from home (I am as well), discount the impact on people's lives who cannot. Same for impact of no school on kids, or delayed surgeries and appointments on overall health outcomes etc.
If most cases can still be traced, and are focused on younger people, rising cases isn't the end of the world. The key metric is hospitalizations rather than cases IMO.