The endorsement lets them write why they support the candidate. Laying out the reasons is what could be convincing, and is what's also being blocked here.
I think the intuition of the parent comment is right, but you also make a fair point[1]. I just wonder if you genuinely believe that any prospective Trump voter could be convinced by any argument to vote for Harris at this point. I mean after all the things that have already been written and said by so many, even by Trump himself, and have failed to convince ~47% of Americans that he's unfit to be the president.
Honestly, I look at the billions of dollars being poured into political ads, and I can't help but think that it's all a tremendous waste because it's hard to imagine that there's anybody left who didn't already form a strong opinion about Trump at some point over the past ten years.
[1] Like even assuming that prospective Trump voters don't read this newspaper, an especially novel or powerful argument could get picked up and spread by other outlets that do reach prospective Trump voters.
Political ads have many purposes, including convincing people to vote for their candidate, instilling a sense of urgency/motivation/purpose to actually get out and vote, and then second order goals like general PR/familiarity for the party, etc.
I don't really expect that there are Trump voters who could be convinced to vote for Harris by the op-ed, but I do think there could be voters who may have been on the verge of reconsidering Trump who may hear something like this story (of Bezos stopping an endorsement) as something that makes them identify their moment of reconsideration as a mistake because they think Bezo's behavior should be perceived as supporting the concept that Democrats and other anti-Trump parties are the ones off-kilter.
