Game, set, match.

"Stat crux dum volvitur orbis' ('The Cross stands while the world turns.") This is the motto of the Carthusian contemplative order.
Well, Our Lord on the Cross crucified was pretty "rigid";... the Holy Cross was and is pretty "rigid". As long as you are 'rigid' about the right things, goodness, and truth, it is a virtue to be 'unchanging'...or 'immemorial.'
The key falsehood of modernism is 'change for change sake.'
The world changes but not the Holy Cross of our Redemption, nor the Church, which changes accidentally, and not essentially, nor the Truths of the apostolic 'depositum fidei.'