I don't see a problem with them handing out priority passes this weekend. There were 5 rides due to be closed, so they have given each person (not everyone got a letter though) a letter worth 5 priority passes for each of the closed rides. Also like Marc said, they can be used all year round, if they were only valid on one day then yes you could say there'd be a problem.
A lot of people were renewing their passes yesterday. So by handing out priority passes at the beginning of the day, and admitting their mistakes/apologizing for rides being closed, they are potentially saving customers who would be put off from renewing after yesterday.
Regarding them dishing out priority passes, wasn't it said that they've been a lot stricter on this in the past season?