I would say it’s both (or neither): if you are always predicting disaster, then your predictions are neither useful nor credible, since you will be wrong most of the time as the long-term trend of the market is upward.
The chance of a crash sometime in the future is 100%. That is credible. Those predictions are completely credible for what most people take as credible, they just aren’t very useful. Markets that rise just because of inflation and population growth aren’t necessarily healthy in the long term. The current great consistent performance of index funds suggests something is up.