Vaccinated people are not submitted to the same constraints (such as mandatory tests for accessing this and that) so carry the virus in more places favourable for transmission. They also don't worry as much about getting the virus (at the same time rightfully so and not rightfully so), so they give up on taking the precautions they took the previous year, and they also do not take a test when symptoms arise but remain light. All this unfortunately compensate for the fact that, individually, they are less subjected to spreading the virus.
Over here, when a vaccinated person tests positive, their pass is not even revoked :-/ Also, in order to promote vaccination, tests which were free have been made paying for non-vaccinated people; so as a perverse result, non-vaccinated people now test less, thus spread more too.
Basically, the current attitude (both individual and official) seem to imply that it does not matter any more to care about spreading the virus, so long as you are relatively/fairly protected against the consequences. I don't think this is going to turn well, but...