Many of the things that people think of as visually distinguishing about frum Jews have actual religious and cultural significance, and it can be very obvious when someone doesn’t know that and does them wrong as a result.
In this picture, the undercover cop is wearing a dark suit and a hat, but is not wearing tzitzit, the religious garment that all men from this community wear pretty much at all times. Not only that, but he has peyot (side curls) but does not have a beard, which flies in the face of the entire religious reason for having peyot. Additionally, although it isn’t shown in the picture here, one of the cops was also wearing a cheap plastic kippah from a completely different movement of Judaism (because I guess all Jews are the same to them?) and was seen blatantly doing things which would be considered to break the Shabbos.
The combined effect is like seeing a woman wearing niquab together with a mini-skirt – it’s not only extremely off, but it’s honestly rather offensive. It looks like they bought a suit and fake, costume peyot from a racist halloween store that also sells costumes of “Mexicans” and “geishas”.
There have been plenty of attempts by the ruling class to pit Jews and the Black community against each other before. Don’t fall for it when they try it now.