Maybe you're inadvertently doing the same here?
Like, on the one hand I get what you're saying and I completely agree. Being a Black woman should not exempt you from the respect your position deserves. That's not cool.
On the other hand, as you said yourself, where was the secret service? They don't care about keeping Drew Barrymore happy or being in front of a camera or any of that. Their job is to keep their charges safe.
No matter what. And yet prep environments their charges are going to be in like nobody's business. There are not surprises very often and when there are they're going to react with a high degree of caution to protect their charge. Again, no matter what.
Which suggests that they already knew how close they'd be sitting because it was planned. Harris has also been accused of being aloof and unapproachable. She's been mostly unseen during her tenure as VP.
Consider who the audience is again. The sitting arrangement visibly displays approachability, warmth, friendliness, engagement. A direct countermeasure to many of the rights wing insults hurled at her.
Personally, I'm going to need more information on this before I go the Harris got disrespected route here. Seems as much or more likely to have been a political tactic to counteract far right propaganda and bigotry that she knew about, maybe even came up with in part or in full, and agreed was the best move to make.
Assume for a moment that's the case. Assume the SS refused her request and demanded an appropriate distance be kept on the grounds of maintaining an aire about the office. Would that not also be disrespect? Why or why not? Under what exact circumstances? Where's the line there? Should she even have a day?