Trump can be bad for the economy and the economy can still be fine. The economy doing well doesn't mean Trump was good for the economy. At the end of the day the policies and actions that have been enacted have not been great tailwinds for the economy regardless of the outcome.
Let me repeat, shouting "stupid Trump is horrible for the economy" from rooftops is not a great political strategy.
In the case it turns out to be false, (and there is a credible chance of that - read the article) it will seem incredibly dishonest.