I thought that prior infection had no relevance for subsequent immunity, otherwise why would they institute mandatory vaccination last year without any kind of

I thought that prior infection had no relevance for subsequent immunity, otherwise why would they institute mandatory vaccination last year without any kind of exception for people who were already previously infected? This kind of obvious incoherency could cause loss of public trust in public health officials and regulations, and that would have been disastrous: people would then start second guessing the rules made by government officials, instead of unquestioningly following them. Only way this could have made sense if vaccination made a much stronger difference to your subsequent immune response than the actual disease itself.