He explained pretty clearly in the article why Trump is objectively wrong.
Except if you do believe the latter, and in that case any discussion is moot.
"A Trump presidency would be a disaster for the American economy."
"He has no real plan to restore economic growth."
"His racist, isolationist policies would divide our country, and American innovation would suffer"
"He's erratic, abusive, and prone to fits of rage. He represents a real threat to the safety of women, minorities, and immigrants."
"Trump shows little respect for the Constitution"
1) Subjective
This is an opinion, not a fact.
2) Objective
I agree. But that does not make him "objectively" wrong.
3) Subjective
Without starting a discussion about Trump alleged racism, whether or not a somewhat isolationist policy would either divide our country or make American innovation suffer is a matter of opinion, not facts. Some other prominent investors seem to disagree.
Besides, examples in our history would tend to show the contrary (I am referring to Roosevelt policies after the '29 crash).
4) Subjective
Unless SCOTUS rules that his stands are unconstitutional, it's only a matter of interpretation.
"American innovation would suffer": Because of economic consequences, so see above.
"He's erratic, abusive, and prone to fits of rage": I don't even know how you can argue against this, just watch one of his speeches.
"He represents a real threat to the safety of women, minorities, and immigrants": He personally is a threat to women, and his policies, such as they are, are now stiring up racial hatred. Again, an objective truth.
"Trump shows little respect for the Constitution": He announced several completely unconstitutional plans, such as suspending the right of US citizens to return to the country if they are Muslims. You don't need a ruling from the Supreme Court on this.