First of all, I have a very low opinion of the electorate. Something like 80 million people are about to vote for Donald Trump. As I said: if you try to spend one minute inside the head of a low-propensity voter, or an "undecided" voter, you will go insane. You certainly will not find anything rational. Low-propensity voters are now heavily Trump leaning. Anything that risks turning out any of them who can barely muster the energy to vote is bad.
Second of all, even if you don't think the remark itself will directly change a single vote, it is going to divert a ton of campaign attention over the next week. Biden had to immediately backtrack from it. Walz has had to defend it. Josh Shapiro has had to defend it. Every major dem surrogate will be asked about it multiple times over the next few days. That is time and energy that should be spent on the messaging the campaign wants to get out. Instead it's spent explaining this away.
There is a reason Trumpworld is going into hyperdrive messaging over this. Of course they're craven hypocrites. Of course they're grievance politics grifters and grubbers whose attempts to appropriate victimhood for themselves and their supporters are laughable. Of course most normie voters will roll their eyes at this. But in a close election, at this stage of the game, anything that drives the campaign off message and into defensive mode is a bad thing. I'm not telling you to wring your hands about it over the next few days but refusing to acknowledge the possibility that it is a real thing that hurts the campaign is foolish.