I don’t see the problem with celebrating, the relief to stay up must have been incredible for them, they aren’t celebrating finishing 17th, they are celebrating pulling off what seemed impossible just a few games back, keeping their top flight status and probably wage increases and hopefully key members of team together and not losing their mates to other clubs.
I think I would be more worried if they didn’t celebrate, to me it shows they care and we can now look forward to being able to push on again next season, a few quality additions to compliment our star performers and it becomes an exciting proposition.